ThingWorx Edge C SDK Release Notes
ThingWorx Edge C SDK Release Notes
The following sections list and describe the new features and the issues fixed in the releases of the ThingWorx Edge C SDK in chronological order, from the current release to the oldest release. To download the latest distribution bundle for your platform, visit the Software Downloads page of the PTC eSupport Portal, https://support.ptc.com/appserver/cs/software_update/swupdate.jsp.
Security
Releases of the ThingWorx Edge C SDK include security-related updates, as follows:
Fixed potential security issues, including items proactively identified by vulnerability scanning software or PTC Quality Assurance testing. Please upgrade as soon as possible to take advantage of these important improvements.
See this technical support article for important recommendations regarding the use and update of third-party software for ThingWorx.
Important Information
Version 2.2.12 has been certified on ThingWorx Platform v.9.1.1 in both single-server and ThingWorx High Availability (HA) Clustering modes.
The following older versions of the ThingWorx Edge C SDK have been certified with ThingWorx Platform 9.0.2 in both single-server and HA Clustering modes:
Previous release — v.2.2.11.562
Oldest release with SNI (Server Name Indication) support — v.2.2.7.1808
Oldest supported release — v.2.2.0.1202
It is recommended to use ThingWorx Platform v.9.0.2 or a later 9.0.x maintenance release with the latest C SDK. You can also use these versions of the C SDK with ThingWorx Platform v.8.5.x.
While these versions of the C SDK have not been certified with ThingWorx Platform, v.9.1.x, they should work with those versions of the platform. Please contact Technical Support if you experience any issues with v.9.1.x.
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C SDK v.2.2.12 
The following table describes the enhancements and the issues fixed in this release:
ID (SFID)
Applies To
Description
Enhancements
CSDK-1835
C SDK
The C SteamSensor application now accepts options and switches on the command line. The new syntax is
[-h hostname] [-p port] [-k key] [-t thingname] [-s] [-c] [-u]
In addition, a usage guide is printed on request or when the command line input is malformed.
CSDK-1883
C SDK
The C SDK has been upgraded to use OpenSSL 1.1.1j.
CSDK-1887
C SDK
A Note in the C SDK help topic, Setting Up Secure Connections, has been updated to explain that the C SDK does not add self-signed certificates to the certificate chain. If configured to accept self-signed certificates, the C SDK accepts self-signed error codes from OpenSSL. Application developers are responsible for setting up security in the strongest acceptable way that owners of the application will be comfortable with.
CSDK-1904
C SDK
The ThingWorx Edge C SDK Developer's Guide has been replaced in the distribution bundle with a one-page PDF that provides a link to the ThingWorx Edge C SDK and SCM Edge Extension for the C SDK Help Center, which has all the content from the original guide, including the content for Using Edge Extensions with the ThingWorx Edge C SDK and the content of the ThingWorx SCM Edge Extension for the ThingWorx Edge C SDK Develoepr's Guide. The Help Center also includes the Support Matrix for the ThingWorx Edge SDKs and a tutorial for the C SDK.
Issues Fixed in This Release
CSDK-1740 (15097067)
CSDK-1867 (15511381, 15352153, 15097067)
C SDK
The SDK will no longer experience hangs while emptying the offline message store after recovering from a network disconnection.
CSDK-1793
C SDK
Windows socket timeouts were added to prevent OpenSSL functions from hanging due to dropped packets.
CSDK-1838
C SDK
The C SDK now generates LONG(23) instead of INVALID BASE TYPE in logs.
CSDK-1859 (15529291)
C SDK
The C SDK will no longer store AUTH or BIND type messages in the offline message store during network disconnections..
CSDK-1860
C SDK
The function twDirectory_MoveFile can now correctly move files between different drives or drive partitions.
C SDK v.2.2.11 
As part of ongoing security improvements, this release of the C SDK include changes to fix potential security issues, as well as additional issues proactively identified by vulnerability scanning software or PTC QA testing. Please upgrade as soon as possible to take advantage of these important improvements
No changes were made to the developer's guide for this release.
C SDK v.2.2.10 
The following table describes the issue fixed in this release.
ID (SFID)
Applies To
Description
CSDK-1809
C SDK v.2.2.10
ExtUseExample does not load dll from proper directory
No changes were made to the developer's guide. In the help center, the changes include the addition of this release note and an update to the support matrix for this release number.
C SDK v.2.2.9 
The following table describes the issues fixed in this release. In addition, it explains a workaround for an issue found during final testing. The issue will be fixed in the next release.
ID (SFID)
Applies to
Description
Issues Fixed
CSDK-1744
C SDK 2.2.9, .NET SDK 5.8.2
Support for Server Name Indication (SNI) for Edge SDK clients when initiating the SSL connection..
When using a reverse proxy to ThingWorx Platform, support for SNI is required in the Edge SDK client or the connection fails.
CSDK-1784
C SDK 2.2.9, WS EMS
TLS host name validation is now supported in the C SDK. For details, refer to the section, TLS Host Name Validation, in the C SDK help center topic, Setting Up Secure Connections.
Known Issue
CSDK-1809
C SDK 2.2.9
On Windows platforms, the ExtUseExample attempts to load dll from wrong directory.
WORKAROUND: As a security measure, the SDK only loads edge extensions from a directory specified by the TWXLIB environment variable. This example attempts to automatically set the variable but uses the wrong directory.
Using your preferred method of setting environment variables on your Windows machine, change the value of the environment variable, TWXLIB from examples/ext to the following path:
examples/ExtUseExample/ext
C SDK v.2.2.8 
The following table lists and briefly describes the changes in this release of the ThingWorx Edge C SDK:
ID (SFID)
Applies to
Description
CSDK-1748 (15119550)
C SDK 2.2.8
The maximum size of the queue for the offline message store should be configurable independently from the size of the queue.
twSubscribedPropsMgr_SetPropertyVTQ() returned an error that adding a property to the queue would exceed the maximum size of the queue for offline message storage.
To resolve this issue, the subscribed property update queue size has been changed to match the twcfg.subscribed_props_queue_size instead of the twcfg.offline_msg_queue_size. The documentation has been updated for this change.
CSDK-1757 (15165179)
C SDK 2.2.8
Add twApi_InitializeWithProxy() function.
A proxy connection to an external instance of ThingWorx failed. The addition of the twApi_InitializeWithProxy() function resolves this issue.
C SDK v.2.2.7 
The following table lists and briefly describes the changes in this release of the ThingWorx Edge C SDK:
ID (SFID)
Applies to
Description
EDGA-1733
N/A
Disabling tunneling causes immediate application segfault.
When the option ENABLE_TUNNELING is turned off, the connection is never initialized at runtime causing an immediate segfault within twApi_TaskerFunction()
This issue is fixed in this release.
C SDK v.2.2.6 
The following table lists and briefly describes the changes in this release of the ThingWorx Edge C SDK:
ID (SFID)
Applies to
Description
CSDK-1529
C SDK 2.2.6
twAPI_Connect() connection retry delay is incorrectly calculated on Linux.
The connection retry delay can help prevent the ThingWorx Platform from being overwhelmed in the scenario where the platform is rebooted and a large number of assets connect simultaneously. The calculation has been fixed in this release.
CSDK-1678
C SDK 2.2.6
ENABLE_TUNNELING causes C SDK build to break on Linux.
This issue is fixed in this release.
CSDK-1697
C SDK 2.2.6
Broken TCP connections can hang the C SDK.
This issue is fixed in this release.
CSDK-1720 (C15034738)
C SDK 2.2.6 and WS EMS 5.4.7
Files between 8114 and 8118 bytes in size fail to transfer to the ThingWorx Platform.
This release contains software fixes for an issue that caused file transfers to the platform to fail if the file was between 8114 and 8118 bytes long.
C SDK v.2.2.5 
The following table lists and briefly describes the change in this release of the ThingWorx Edge C SDK:
ID (SFID)
Applies to
Description
Enhancements
CSDK-1284
C SDK 2.2.5
In previous releases, MAX_ENTITY_NAME_LENGTH was defined in multiple places with different values, as follows:
twApi.c — 256
twOfflineMsgStore.c — 512
twInfoTable.c — 2048
twMessages.c — 1024
The correct value for MAX_ENTITY_NAME_LENGTH is 256. It is now defined ONLY in twConstants.h as MAX_ENTITY_NAME_LEN This file is now #include'd in all of the .c files listed above. Refer to the table listing the files in <csdk>/src/api in Installing and Navigating the Directories of the C SDK.
CSDK-1533
C SDK 2.2.5
CMake ENABLE_OFFLINE_MSG_STORE_FILE option is now on by default. Refer to Configuring Options for a CMake Build.
CSDK-1629
C SDK 2.2.5
Add Event Unregister Callback.
A new callback, twApi_UnregisterEventCallback, has been added to the twApi.h file, with its implementation in twApi.c. Refer to Defining Events for details.
CSDK-1686
CSDK 2.2.5
Refactor C SDK CMake Files
The C SDK CMake files have been refactored, following the best practices recommended in Professional CMake by Craig Scott (available at https://crascit.com/professional-cmake). Refer to How to Build an Edge Application with CMake.
CSDK-1687
C SDK 2.2.5, .NET SDK 5.8.1, WS EMS 5.4.7
Integrate OpenSSL 1.1.1c into C SDK
OpenSSL 1.1.1c has been added to the C SDK for all supported processors and operating systems. In addition, the non-FIPS OpenSSL 1.0.2 libraries have been removed from the C SDK. Finally, the OpenSSL 1.0.2l FIPS libraries have also been removed from the C SDK. This release of the C SDK does not support FIPS. Refer to Using SSL/TLS for Security
CSDK-1694
C SDK 2.2.5, .NET SDK 5.8.1, WS EMS 5.4.7
TLS 1.3
TLS 1.3 support requires Java 11. Although the ThingWorx Platform has been upgraded in v.9.1.x to run on Java 11, it does not yet fully support TLS 1.3. Continue to use the latest SSL/TLS version prior to TLS v.1.3.
CSDK-1695
C SDK 2.2.5
The C SDK third-party libraries that PTC has modified (libcfu and ntlm) are built in the csdk project. The remaining third-party libraries are in a statically-linked library. Previously, all third-party code was built in the csdk project. After extracting the distribution bundle, you will find the modified libraries as <csdk>/forkedThirdParty. The remaining third-party libraries are compiled into a library called twThirdParty. The libraries compile with warning disabled.
The end result is that when building the C SDK, you should not notice any difference. There are no additional library files to copy.
OpenSSL is in the <csdk>/lib subdirectory. Note that OpenSSL is pre-built so that it does not need to be compiled, just linked.
Issues Fixed
CSDK-1526
C SDK 2.2.5
ENABLE-OFFLINE_MSG_STORE_FILE=ON causes access violation or core dumps.
This issue is fixed in this release. Note that ENABLE_OFFLINE_MSG_STORE_FILE is now set to ON by default.
CSDK-1541
C SDK 2.2.5
The data_size argument of the ForEach handler is not needed and could cause confusion.
This argument has been removed from the twList_Foreach signature:

int twList_Foreach(twList *list, twForEachHandler listHandler, void *userData){
struct ListEntry * node = NULL;
int processedCount = 0;
if (!list || list->count == 0)
return 0;

twList_Lock(list);
node = list->first;
while (node) {
processedCount++;

if(listHandler(node,sizeof(node),node->value,
sizeof(node->value),userData)!=0)
// ~~~~~~~~~~~~~~~~~~~
break;
node = node->next;
}
twList_Unlock(list);
return processedCount;
}
For information on using the twList_ForEach() function, refer to Using Linked Lists, Maps, and Dictionaries
CSDK-1682 (PSPT-7364)
C SDK 2.2.5
When logging a connection attempt, the C SDK prints extra slash in the connection URL that technically does not exist in the actual connection URL.
The extra forward slash is no longer printed when writing log messages.
CSDK-1700 (14994157)
C SDK 2.2.5
File Transfer Subsystem Copy service failing with error Source file checksum did not match with target fail checksum.
This issue is fixed in this release. For information about using the Copy service to transfer files, refer to Transfer Files Using the Copy Service in the "How To" section below.
CSDK v.2.2.4 
The following table lists and briefly describes the change in this release of the ThingWorx Edge C SDK:
ID (SFID)
Applies to
Description
Issue Fixed
CSDK-1601
C SDK 2.2.4
twW_SetApiProperties() call accepts a char * rather than a twPasswdCallbackFunction for a clientKeyPassphrase.
This issue is fixed in this release.
C SDK v.2.2.3 
This release of the C SDK resolves the following issue found in the C SDK v.2.2.2 distribution bundle:
ID (SFID)
Applies to
Description
CSDK-1621
C SDK 2.2.3
The file transfer example in the v.2.2.2 distribution should NOT be used. This release removes this example. The Example will be updated for customer use and included in the next release.
C SDK v.2.2.2 
This release of the C SDK upgrades the version of OpenSSL from 1.0.2q to 1.0.2r. With this release, the C SDK, its Edge Extensions, and the ThingWorx SCM Edge Extension for the C SDK are now in their own help center, which provides a quickstart that links you to tutorials in the ThingWorx Developer Zone as well as the tutorial and information common to all Edge SDKs.
This release includes the following software fixes.
ID (SFID)
Applies to
Description
CSDK-1390 / PSPT-5600 (14703870 / 14517496)
C SDK 2.2.2 and 2.2.3
The C SDK could not be compiled with OpenSSL 1.1.
CAUSE: A reference in twSig.c to an OpenSSL struct field that is no longer publicly reachable, as of OpenSSL 1.1.
RESOLUTION: The reference has been replaced with the public accessor method, which allows the SDK to build and is compatible with the OpenSSL 1.0.x versions shipped with the C SDK and with user-implemented 1.1.x solutions.
C SDK-1536
C SDK 2.2.2 and 2.2.3
Threading Model MULTI not listed in the source file, twApi.h.
The twApi.h file now contains information on the multi-threaded model, which you should be using by default. The multi-threaded model is strongly recommended to improve the performance of your client applications. For information about protecting access to certain data structures, refer to "Synchronization Functions", in the ThingWorx C SDK Developer's Guide or in the C SDK Help Center.
C SDK-1576
C SDK 2.2.2 and 2.2.3/ WS EMS 5.4.6
Many port parameters in functions should be of type uint16_t instead of int16_5.
To prevent network errors and allow the full range of network ports to be used, the port parameters used in C SDK functions are now of type uint16_5. This fix resolves an issue in WS EMS 5.4.6 (EDGA-1097).
C SDK v.2.2.1 
This release of the C SDK includes the software fixes from v.2.2.0 plus, as part of PTC’s continuous efforts to improve security, a security enhancement. This release provides the following enhancement:
ID (SFID)
Applies to
Description
CSDK-1315 (14593755)
C SDK v.2.2.1
Release 2.2.1 of the C SDK includes non-FIPS OpenSSL 32– and 64–bit libraries, version 1.0.2q, which, on Windows platforms is based on Visual Studio 2015 runtime library. The FIPS OpenSSL libraries of this SDK are still based on Visual Studio 2012 and therefore still are version 1.0.2l of the OpenSSL libraries.
In addition, as of this release, the axTLS library is no longer provided in the distribution bundles of the C SDK.
C SDK v.2.2.0 
This release of the C SDK includes the following enhancements and software fixes::
ID (SFID)
Applies to
Description
Enhancements
CSDK-
C SDK 2.2.0
Security Enhancement
For this release, the way that strings of type PASSWORD are provided to the SDK has changed. This includes application keys, digests, passwords for certificates (passphrase for keystore), and passwords for proxy server users. For details about this enhancement, refer to the ThingWorx Edge C SDK Developer's Guide that accompanies the C SDK or the C SDK Help Center..
CSDK-1160 and C SDK 1302
C SDK 2.2.0
The C SDK has been updated to support Microsoft Visual Studio 2017 in addition to its support for 2012 and 2013.
Issues Fixed in This Release
CSDK-1165 (13968996)
C SDK 2.2.0, WS EMS 5.4.5
Sometimes when starting the C SDK, a linking error occurs (0x18)
An intermittent linking error occurs when starting the C SDK.
CAUSE: The twCSdk.dll loads consistently at the address that OpenSSL wants to occupy when this error is encountered. Since OpenSSL is a dependency of the C SDK, which is a dependency of the top level executable, Windows always loads the C SDK dll before it loads OpenSSL. You can view this in an application that allows you to view the dependency order as a 'tree'.
WORKAROUND: Make the following code and configuration changes to force libeay32.dll be to loaded before the C SDK in your final application:
1. In CMake build files for the C SDK, .NET SDK, and any other application that depends on OpenSSL, libeay32.dll should be specified first in the linker order. (Windows only)
2. In the main() function of your C or .NET application, you need to make a call to some function that lies in libeay32.dll. It can just be a call to get the version, as shown below:
const char * version_test = SSLeay_version(SSLEAY_VERSION);
These changes force the executable to depend directly on libeay32.dll, which makes Windows load it before it loads the C SDK.
CSDK-1175
C SDK 2.2.0 and WS EMS 5.4.5
"twMap_Add: parse function returned null" is logged whenever starting WS EMS v.5.4.0
This issue is fixed in this release of the C SDK.
CSDK-1290
C SDK 2.2.0
C SDK build depends on relative path.
This issue is fixed in this release.
CSDK-1291
C SDK 2.2.0
snprintf redefinition
This issue is fixed in this release. snprintf's are now wrapped in #ifndef's.
CSDK-1319
C SDK 2.1.2 through 2.2.0, WS EMS 5.4.5
twApi_Connect() can block and never return in some cases.
If no receive timeout value is set on the underlying socket, the twApi_Connect() function can sometimes block and never return. The C SDK uses blocking sockets where the edge device must receive a TCP three-way handshake before this function will return. By default, the TCP receive timeout is set to 0, which means that it will never time out. In cases where the remote host never sends any packages to the edge device, the twApi_Connect() function will never time out and block forever.
RESOLUTION: Set a receive timeout value on the socket, using the setsocketopts() call. For example:
DWORD timeout = 60000; // 60 seconds in milliseconds
setsockopt (t->connection->sock, SOL_SOCKET, SO_RCVTIMEO,
(char *)&timeout, sizeof (timeout));
CDK-1340
C SDK 2.1.2 through 2.2.0, WS EMS 5.4.5
This issue has been resolved as part of PTC’s continued investment in helping customers reduce risks associated with security threats.
C SDK v.2.1.5 
This release includes software fixes for the following issue:
ID (SFID)
Applies to
Description
CSDK-1294 (14545563)
C SDK 2.1.6, WS EMS 5.4.5
WS EMS 5.4.1 - GetDirectoryStructure returns wrong result when sub-directory is named with 1-digit number and deep sub-folders are not returned.
This issue is fixed in this release. GetDirectoryStructure will now return the correct result when a sub-directory has a 1-digit or 1-character name.
C SDK v.2.1.4 
This release includes software fixes for the following issue:
ID (SFID)
Applies to
Description
CSDK-1278 (14215962 and 14231681)
C SDK 2.1.4
SCM file transfer fails on large files and remains .part at destination.
This issue is fixed this release.
* 
The messageChunkSize must be less than (or equal to) the value of frameSize.
C SDK Version 2.1.3 
With this release, the C SDK supports the separately available ThingWorx Software Content Management (SCM) Edge Extension (v1.0.0). Refer to the release notes for the SCM Edge Extension for details. To use ThingWorx SCM, you also need the SCM extension for ThingWorx Platform (formerly part of ThingWorx Utilities).
ID (SFID)
Applies to
Description
Issues Fixed in This Release
CSDK-80
C SDK 2.1.3
messageChunkSize and frameSize (twApi_Initialize and twWs_Create) have conflicting error logic.
This issue is fixed in this release.
CSDK-787
C SDK 2.1.3
twMap should not produce an error when a duplicate key is added.
The log message, twMap_Add: key already exists, deleting new entry, now logs at the DEBUG level of log messages because this behavior is acceptable.
CSDK-1104
C SDK 2.1.3
CSDK 2.0.0 added an init callback that is fired when the SDK is initialized by twApi_Initialize. The registration function twApi_RegisterInitCallback for this callback allows the user to provide a void* 'user data' pointer, which is cached off in a data structured owned by twcfg. However, the user data is not actually passed into the callback when it is invoked.
This issue is fixed in this release.
CSDK-1257
C SDK 2.1.3
Circular include dependency in C SDK.
The enum LogLevel definition has been moved from the twLogger.h file to the twDefinitions.h file. In addition the #include twLogger.h line has been removed from the twOSPort.h file.
C SDK Version 2.1.2 
Issue ID (SFID)
Applies to
Description
Enhancements
CSDK-1170
C SDK 2.1.2
Improve logging for staging directory failures.
A file transfer failed to complete when the staging directory was on a separate partition (RAMDisk) from the final destination.
The resolution of this issue was additional logging around the failure (a DEBUG build) to help resolve a file transfer failure in twListEntities().
CSDK-1195
C SDK 2.1.2
Add support to the ThingWorx C SDK to customize what cipher suites are used at runtime.
The C SDK now allows developers to customize the cipher suites to use at run time by specifying a string that contains the cipher suite configuration in a new parameter, cipher_set, in the twcfg structure. For more information, refer to the section, Support for Cipher Suites, in the C SDK section of the ThingWorx Edge SDKs and WS EMS Help Center or in the ThingWorx Edge C SDK Developer's Guide, v.2.1.2, which is available in the distribution bundle or through the Reference Documents page of the PTC Support site.
Issues Fixed
CSDK-1185
CSDK 2.1.2
Race condition prevents FIPS mode from being used on WebSocket connection.
Due to a race condition, calls to twApi_EnableFipsMode() would not enable FIPS mode on the WebSocket connection to the ThingWorx Platform.
CSDK-1196
C SDK 2.1.2
WebSocket compression header message is formatted incorrectly
The WebSocket compression header message was formatted incorrectly, preventing compression from being enabled.
This issue is fixed in this release.
CSDK-1217
C SDK 2.1.2
C SDK mishandles incoming fragmented WebSocket messages (continuation frames).
The C SDK did not correctly handle incoming WebSocket messages that were fragmented into multiple frames. Instead of concatenating the frames into a single message before attempting to deserialize the AlwaysOn payload, the SDK instead treated the first and all subsequent fragments as whole messages, parsing each of their payloads as individual AlwaysOn messages
This issue is fixed in this release. Incoming WebSocket messages that are fragmented into multiple frames are now concatenated into a single message before the SDK attempts to deserialize the payload.
CSDK-1225
C SDK 2.1.2
Compression race condition allows corrupt messages to be sent to the platform.
With this release of the C SDK, binary data added to the sliding window compression context is sent out the WebSocket in the exact same order.
CSDK-1226
C SDK 2.1.2
C SDK Tunnel Manager calls incorrect API when setting client CA list.
In twTunnel_Create() the tunnel manager incorrectly calls twTlsClient_SetCertificateChain() when setting the CA Certificate list. This issue prevented the WebSocket tunnel from working correctly when certificate validation was enabled.
The tunnel manager now correctly calls twTlsClient_SetClientCaList().
CSDK-1227
C SDK 2.1.2
C SDK fails to send messages when the message serializes as a fragmented WebSocket message.
Similar to CSDK-1217, the CSDK would not generate fragmented WebSockets (that is, WebSockets whose message size is greater than the message chunk size, or 8k by default). Rather than generate the fragmented message, it failed to send the whole message.
This issue occurred when compression was enabled and file transfers of random or compressed data were being performed from the edge up to the platform.
This issue is fixed in this release. File transfers from the edge up to the platform should now complete successfully when compression is enabled and the files contain random or compressed data.
CSDK-1231
C SDK 2.1.2
Manage remote property bindings - fails with large property count with long property names.
When doing remote property binding in ThingWorx Composer, no values were displayed for a large property count, where the property names were long.
This issue is fixed in this release. The maximum string length (set in max_string_prop_length) for property and response messages has been adjusted from 16384 bytes to 1MB, and this value is now configurable.
C SDK Version 2.1.1 
Issue ID (SFID)
Applies to
Description
CSDK-1169 (13968996)
C SDK 2.0.5
Offline Message Store Does Not Transfer Multiple Chunks to the Platform
The offline message store does not transfer any property value information when the offline message store file size is larger than 8 KB. This issue occurred with C SDK v.2.0.5 and ThingWorx Platform v.8.0.3.
CAUSE: When creating the large offline messages (>8 KB), the C SDK breaks them up into multi-part messages. When flushing the offline message store, the C SDK is generating new request ID’s for each message. The platform cannot sync up the multi-part request because it expects the related messages to have the same request ID.
This issue is fixed in this release.
C SDK Version 2.1.0 
Issue ID
Applies to
Description
New in This Release
CSDK-976 / EDGE 2274
C SDK 2.1.0
Enable WebSocket Compression: C SDK
Refer to the ThingWorx Edge C SDK Develoepr’s Guide for more information about compression.
Issues Fixed in This Release
CSDK-1119
C SDK 2.1.0
twGetFileChecksum can access freed memory.
ThetwGetFileChecksum function, which is called by the platform after a file transfer completes, can access memory that has been freed by another thread, crashing the hosting application. This occasionally happens in normal circumstances when a file transfer is canceled (when it is nearly complete).
This issue is fixed in this release.
CSDK-1094
C SDK 2.1.0
Missing init Function in Windows Extension Library throws Exception.
When an extension library is renamed or built incorrectly, its init function can be missing.
RESOLUTION: With this release, if this situation occurs, an error message is presented and the call to load the library is terminated gracefully.
C SDK Version 2.0.5 
Issue ID
Applies to
Description
CSDK-1148
C SDK 2.0.4, .NET SDK 5.7.4
C SDK fix for .NET SDK 5.7.4.
The .NET SDK was observed to not work with OpenSSL, occasionally hanging, and initializaing very slowly. twApi_RegisterInitCallback() as allocating the incorrect memory size from the heap and overwriting neighboring heap space. This callback function now allocates the correct memory size.
C SDK Version 2.0.4 
Issue ID
Applies to
Description
CSDK-1146
C SDK 2.0.3
The twMap utility was leaking in v.2.0.3. This issue is fixed in this release.
C SDK Version 2.0.3 
Issue ID
Applies to
Description
CSDK-1141
C SDK 2.0.2
axTLS TW_NEW_SERVER implementation ignores use_default_certificate switch.
The TW_NEW_SERVER function in twAxTls.h does not support the flag, use_default_certificate in the same way that twOpenSSL.h does..
This issue is fixed in this release.
CSDK-1125
C SDK 2.0.0
Incorrect comparison operation prevents TLS library information from being printe3d at startup
This issue is fixed in this release.
C SDK Version 2.0.2 
Issue ID
Applies to
Description
CSDK-1112
C SDK 2.0.0
Causing a disconnect during asynchronous publish prevents value from being published to the platform.
A new C SDK API function clears the cached SPM list of currentValueson disconnect. This new function is intended to ensure values are published to the platform as expected.
CSDK-850
C SDK 2.0.0
Only one timed-out message is reaped per iteration (every 50 seconds).
The function, twMessageHandler_CleanupOldMessages, is expected to clean up all messages that have timed out, but it only cleaned up the first message.
This issue is fixed in this release. The function, twMessageHandler_CleanupOldMessages, now works as expected. All timed-out messages are cleaned up when this function is called.
CSDK-197
C SDK 2.0.0
C SDK leaks memory in twMap_Create().
The twMap_Create() function allocates memory that was never freed.
This issue is fixed in this release.
C SDK Version 2.0.1 
Issue ID
Applies to
Description
CSDK-1107
C SDK 2.0.0
Race condition causes the queue size of the SubscribedPropertyManager (SPM) to underflow and reject all data updates.
The queueSize counter was exposed to concurrent access, which caused it to be updated incorrectly. Afterwards, as updates were flushed out of the SPM, the unsigned value underflowed, leading the SDK to reject all incoming property updates with a message that the maximum value for the queue size would be exceeded if the property specified in the error message were added.
This issue is fixed in this release.
C SDK Version 2.00 
Issue ID (SFID)
Applies to
Description
New in This Release
CSDK-989
C SDK 2.0.0
To prevent integer overflows when defining connect retries, the twApi_Connect() method signature has changed to accept "int16_t retries" instead of "int32_t retries".
CSDK-953
C SDK 2.0.0
Print Version Info on Startup
When the C SDK is started it prints the following version information:
Version number of the SDK
SSL library being used — OpenSSL, OpenSSL-FIPS, NoTls, or axTLS
Version number of the SSL library being used.
Whether FIPS is enabled
CSDK-952
C SDK 2.0.0
Create SSL Compatibility Matrix
The document, ThingWorx Edge Requirements and Compatibility Matrix, for the Edge SDKs, WS EMS, and Connection Services has been updated to include a matrix for C SDK releases and the compatible axTLS and OpenSSL versions.
CSDK-938
C SDK 2.0.0
Support Loading OpenSSL from system libs
To load OpenSSL from system libs, set the following environment variables to your OpenSSL include/lib directories and compile:
THINGWORX_CSDK_OPENSSL_INCLUDE_DIR
THINGWORX_CSDK_OPENSSL_LIB_DIR
CSDK-932
C SDK 2.0.0
Distribute OpenSSL in the C SDK
Starting with this release, the C SDK distribution bundles for the supported platforms include the appropriate OpenSSL binaries, v. 1.0.2k of OpenSSL.
* 
The C SDK build process will now default to an OpenSSL-based build instead of an axTLS-based build. axTLS has been removed due to issues with SSL/TLS certificate configurations and known bugs related to accepted cipher suites in Tomcat.
Issues Fixed in This Release
CSDK-911 (13591031)
C SDK 1.3.4
SDKClient Code Does Not Receive the Actual Exception Message Thrown from ThingWorx Service.
CAUSE: The SDK client returned a Generic Exception instead of the actual exception Reason thrown in a ThingWorx local service. The SDK should return the actual Reason so that a developer can take action on the error.
RESOLUTION: The SDK will now return the actual exception message as thrown in the service. The C SDK function twApi_InvokeServiceAsync() invokes a service asynchronously and can be passed a callback. Upon service completion, the the “Reason” field of the response, is passed to the callback, providing a way for an application to react to the exception.
CSDK-891 (13647664)
C SDK 1.3.2.636
C SDK Crashes with Null Pointer Exception in twList_Create() Function.
If the allocation of the mutex failed, the list was deleted and the list pointer was set to null (0). Then the list->delete_function assignment statement was executed. The list became NULL, causing a crash.
This issue is fixed in this release.
CSDK-888 (13338641)
C SDK
C SDK can reuse request ids, which can lead to unexpected behavior.
The C SDK was observed sending two requests with the same request id. The first request timed out, while the second request appeared to succeed. Even though the second request was successful, the session id received from ThingWorx Platform for the authentication request was invalid (–1). All follow-on communications failed with an invalid session error.
CAUSE: When a persisted message is resent, it should get a new request id to avoid collisions. Instead of requesting a new id, the persisted message took an id from an active message and incremented that message’s id. So, when a new message requested a new id, a duplicate id was issued.
RESOLUTION: The resolution is an interface for all messages to use to get a request id, so that collisions can no longer occur.
CSDK-781
C SDK, v.1.3.0, 1.4.0, and 1.5.1
Numeric Truncation Error
CAUSE: connect_retries was the same type everywhere EXCEPT for the input to twApi_Connect().
RESOLUTION: The twApi_Connect() method signature has changed so that it is an int16_t. This change will prevent integer overflows when defining connect retries.
CSDK-32
C SDK 1.3.2
SetGatewayType and SetGatewayName C SDK API Functions Do Not Check If the API Has Been Initialized
RESOLUTION: these two functions do check whether the API has been initialized. (that is, they make this check: if (!tw_api) return TW_NULL_API_SINGLETON).
Known Issue
CSDK-1100
C SDK 2.0.0
Linux-ARM cross compilation issue.
During testing of C SDK 2.0.0, it was discovered that cross compiling to ARM on systems without hardware floating point was having problems locating the shared libraries used in its tool chain. This issue affects devices that do not support or do not have the resources to do on-board compilations.
This issue is a configuration issue with CMake. CMake was introduced in version 1.4.0 of the C SDK.
C SDK Version 1.5.3 
Issue ID (SFID)
Applies to
Description
Issues Fixed in This Release
CSDK-1123
C SDK
Memory leak discovered in C SDK application.
This issue is fixed in this release.
Known Issues
CSDK-916
C SDK
C SDK v.1.4.x and 1.5.x releases use axTLS v.2.1.2. These versions of the C SDK were unable to connect to SSL Tomcat servers that did not specify pathLenConstraint in their root certificate (which include PTC Cloud Services production instances of ThingWorx Platform). A partial fix for this issue was provided in release 1.5.0 (refer to CSDK-933 in the notes for that release) for the problem with the root certificate in a chain, where the chain consists of the root, one intermediate certificate (with or without pathLenConstraint), and a server certificate (which is not a CA so constraints are irrelevant). However, the problem can still occur if a certificate chain has more than one intermediate certificate that does not have pathLenConstraint. For information about the pathLenConstraint parameter, refer to RFC 5280, section 4.2.1.9..
IMPORTANT! This issue is present only when using axTLS builds of the C SDK v.1.4.x and 1.5.x. OpenSSL-based C SDK builds do not experience this issue.
CSDK-911 (13591031)
C SDK
SDK client code does not receive the actual exception message thrown from ThingWorx service
Invoking a service from ThingWorx SDK client returns a Generic Exception and not the actual exception thrown in ThingWorx local service. Without the actual exception, a developer cannot take action based on the exception.
CSDK-891 (13647664)
C SDK
C SDK crashes with null pointer exception in twList_Create function.
If the allocation of the mutex fails, the list is deleted and the ‘list’ pointer is set to null (0). The list delete_function assignment statement is then executed. The ‘list’ will be NULL at this time, causing a crash.
CSDK-888 (13338641)
C SDK
C SDK can reuse request ids, which can lead to unexpected behavior.
The C SDK was observed sending two requests with the same request id. Request 1 timed out, and request 2 appeared to succeed. However, the session id received from the platform for the authentication request was invalid, causing all follow-on communication to fail with an invalid session error.
CSDK-115 (13373562)
C SDK
Size of the file limited by twcfg.offline_msg_queue_size is not honored.
When using the subscribed property manager and a device is offline when calling twApi_PushSubscribedProperties(), the property values are written to a persisted file named subscribed_props.bin. The size of the file should be limited by the variable twcfg.offline_msg_queue_size. However, the actual file will grow considerably larger than the value specified by twcfg.offline_msg_queue_size.
C SDK Version 1.5.2 
Issue ID (SFID)
Applies to
Description
Issues Fixed in This Release
CSDK-978
C SDK
NUMBER updates dropped when the previous update’s value was 0.
For properties of type NUMBER, the C SDK always used {{0}} as the incoming value when doing VALUE and DEADBAND delta comparisons. Therefore, if the previous value of a property was {{0}}, the next incoming value would not be sent to the platform, resulting in an error message.
NOTES:
This issue only affected properties of type NUMBER.
This issue did not affect push type ALWAYS.
For DEADBAND properties, every update after the '0' update was ignored
This issue is fixed in this release. Updates of DEADBAND properties are no longer ignored after the ‘0’ update.
CSDK-968
C SDK
Removing property with push type ALWAYS causes null pointer de-reference.
Unregistering a property callback for a property with push type ALWAYS on a Thing with other properties caused a null pointer de-reference in the stack, crashing an application or corrupting SDK structures.
This issue is fixed in this release. The last pointer is now checked, preventing the null pointer de-reference.
Known Issues
CSDK-916
C SDK
C SDK v.1.4.x and 1.5.x releases use axTLS v.2.1.2. These versions of the C SDK were unable to connect to SSL Tomcat servers that did not specify pathLenConstraint in their root certificate (which include PTC Cloud Services production instances of ThingWorx Platform). A partial fix for this issue was provided in release 1.5.0 (refer to CSDK-933 in the notes for that release) for the problem with the root certificate in a chain, where the chain consists of the root, one intermediate certificate (with or without pathLenConstraint), and a server certificate (which is not a CA so constraints are irrelevant). However, the problem can still occur if a certificate chain has more than one intermediate certificate that does not have pathLenConstraint. For information about the pathLenConstraint parameter, refer to RFC 5280, section 4.2.1.9..
IMPORTANT! This issue is present only when using axTLS builds of the C SDK v.1.4.x and 1.5.x. OpenSSL-based C SDK builds do not experience this issue.
CSDK-911 (13591031)
C SDK
SDK client code does not receive the actual exception message thrown from ThingWorx service
Invoking a service from ThingWorx SDK client returns a Generic Exception and not the actual exception thrown in ThingWorx local service. Without the actual exception, a developer cannot take action based on the exception.
CSDK-891 (13647664)
C SDK
C SDK crashes with null pointer exception in twList_Create function.
If the allocation of the mutex fails, the list is deleted and the ‘list’ pointer is set to null (0). The list delete_function assignment statement is then executed. The ‘list’ will be NULL at this time, causing a crash.
CSDK-888 (13338641)
C SDK
C SDK can reuse request ids, which can lead to unexpected behavior.
The C SDK was observed sending two requests with the same request id. Request 1 timed out, and request 2 appeared to succeed. However, the session id received from the platform for the authentication request was invalid, causing all follow-on communication to fail with an invalid session error.
CSDK-115 (13373562)
C SDK
Size of the file limited by twcfg.offline_msg_queue_size is not honored.
When using the subscribed property manager and a device is offline when calling twApi_PushSubscribedProperties(), the property values are written to a persisted file named subscribed_props.bin. The size of the file should be limited by the variable twcfg.offline_msg_queue_size. However, the actual file will grow considerably larger than the value specified by twcfg.offline_msg_queue_size.
C SDK Version 1.5.1 
Issue ID (SFID)
Applies to
Description
Issues Fixed in This Release
CSDK-944
C SDK
Poor performance publishing to entities with high property counts.
With changes made for CSDK-743 and CSDK-837, the SetPropertyVTQ function was entering into a linear search through a list of properties for the relevant entity. This linear traversal led to poor performance on entities that had very high property counts (several hundred or more).
To resolve this issue, the list used to implement the most-recent value cache has been replaced with a dictionary, which allows lookups to happen without adversely affecting performance (CPU usage). It is important to note that for implementations that have far fewer properties, this issue should not occur with releases 1.4.x or 1.5.0 (up to 100 Things, each with 100 properties, for example).
Known Issues
CSDK-916
C SDK
C SDK v.1.4.x and 1.5.x releases use axTLS v.2.1.2. These versions of the C SDK were unable to connect to SSL Tomcat servers that did not specify pathLenConstraint in their root certificate (which include PTC Cloud Services production instances of ThingWorx Platform). A partial fix for this issue was provided in release 1.5.0 (refer to CSDK-933 in the notes for that release) for the problem with the root certificate in a chain, where the chain consists of the root, one intermediate certificate (with or without pathLenConstraint), and a server certificate (which is not a CA so constraints are irrelevant). However, the problem can still occur if a certificate chain has more than one intermediate certificate that does not have pathLenConstraint. For information about the pathLenConstraint parameter, refer to RFC 5280, section 4.2.1.9..
IMPORTANT! This issue is present only when using axTLS builds of the C SDK v.1.4.x and 1.5.x. OpenSSL-based C SDK builds do not experience this issue.
CSDK-911 (13591031)
C SDK
SDK client code does not receive the actual exception message thrown from ThingWorx service
Invoking a service from ThingWorx SDK client returns a Generic Exception and not the actual exception thrown in ThingWorx local service. Without the actual exception, a developer cannot take action based on the exception.
CSDK-891 (13647664)
C SDK
C SDK crashes with null pointer exception in twList_Create function.
If the allocation of the mutex fails, the list is deleted and the ‘list’ pointer is set to null (0). The list delete_function assignment statement is then executed. The ‘list’ will be NULL at this time, causing a crash.
CSDK-888 (13338641)
C SDK
C SDK can reuse request ids, which can lead to unexpected behavior.
The C SDK was observed sending two requests with the same request id. Request 1 timed out, and request 2 appeared to succeed. However, the session id received from the platform for the authentication request was invalid, causing all follow-on communication to fail with an invalid session error.
CSDK-115 (13373562)
C SDK
Size of the file limited by twcfg.offline_msg_queue_size is not honored.
When using the subscribed property manager and a device is offline when calling twApi_PushSubscribedProperties(), the property values are written to a persisted file named subscribed_props.bin. The size of the file should be limited by the variable twcfg.offline_msg_queue_size. However, the actual file will grow considerably larger than the value specified by twcfg.offline_msg_queue_size.
C SDK Version 1.5.0 
Issue ID (SFID)
Applies to
Description
New in This Release
CSDK-894
C SDK
Implement Idle Transfer Monitor in twApi_TaskerFunction
File transfer timeouts are now evaluated independent of the FileManager singleton. The new idel file transfer monitor is in twApi.c (1776) within the twApi_TaskerFunction.
CSDK-864
C SDK
Deadband Push Type
To support KEPServer users, the C SDK supports a new push type that implements a cumulative Threshold to provide deadband support.. The deadband push type is implemented as absolute (no percentages). It follows the existing threshold field limits.
Issues Fixed in This Release
CSDK-933
C SDK, WS EMS
axTLS should ignore pathLenConstraint on root certificates
axTLS in the C SDK now accepts null pathLenConstraint for certificates. With this change, even if the root certificate of a certificate chain does not have pathLenConstraint, the C SDK can still connect to a platform. If one (and only one) intermediate certificate in the chain does not have pathLenConstraint, the C SDK can still connect. However, if the certificate chain has additional intermediate certificates that do not have pathLenConstraint, the C SDK cannot connect. This change applies only to root certificates in the chain. For information about the pathLenConstraint parameter, refer to RFC 5280, section 4.2.1.9..
IMPORTANT! Refer to the Known Issue, CSDK–916.
CSDK-837 (13573872)
C SDK
Queue size in SetPropertyVTQ is incorrect when enabling fold
The offline message storage queue size was incorrect with folding enabled. The QueueValueForSending function in the file,twSubscribedProps.c, judged based on the fold parameter. If the value of the fold parameter is true, it needs to find and replace the property or add it if it does not exist. So, if the property exists in the offline message store fle, it will be replaced instead of added as a new property. The >queueSize should not change when an existing property is replaced, but in fact it did change.
This issue is resolved in this release.
CSDK-883
C SDK
Quality Only Changes on VALUE Properties Are Not Propagated.
If a property was using a push type of VALUE, and (only) the quality for that property changed, that update was not propagated to ThingWorx platform.
A VALUE push type is now handled such that an update is pushed based on either a value or quality change.
Known Issues
CSDK-916
C SDK
C SDK v.1.4.x and 1.5.0 releases use axTLS v.2.1.2. These versions of the C SDK were unable to connect to SSL Tomcat servers that did not specify pathLenConstraint in their root certificate (which include PTC Cloud Services production instances of ThingWorx Platform). A partial fix for this issue is provided in release 1.5.0 (refer to CSDK-933 above) for the problem with the root certificate in a chain, where the chain consists of the root, one intermediate certificate (with or without pathLenConstraint), and a server certificate (which is not a CA so constraints are irrelevant). However, the problem can still occur if a certificate chain has more than one intermediate certificate that does not have pathLenConstraint. For information about the pathLenConstraint parameter, refer to RFC 5280, section 4.2.1.9..
IMPORTANT! This issue is present only when using axTLS builds of the C SDK v.1.4.x and 1.5.0. OpenSSL-based C SDK builds do not experience this issue.
CSDK-911 (13591031)
C SDK
SDK client code does not receive the actual exception message thrown from ThingWorx service
Invoking a service from ThingWorx SDK client returns a Generic Exception and not the actual exception thrown in ThingWorx local service. Without the actual exception, a developer cannot take action based on the exception.
CSDK-891 (13647664)
C SDK
C SDK crashes with null pointer exception in twList_Create function.
If the allocation of the mutex fails, the list is deleted and the ‘list’ pointer is set to null (0). The list delete_function assignment statement is then executed. The ‘list’ will be NULL at this time, causing a crash.
CSDK-888 (13338641)
C SDK
C SDK can reuse request ids, which can lead to unexpected behavior.
The C SDK was observed sending two requests with the same request id. Request 1 timed out, and request 2 appeared to succeed. However, the session id received from the platform for the authentication request was invalid, causing all follow-on communication to fail with an invalid session error.
CSDK-115 (13373562)
C SDK
Size of the file limited by twcfg.offline_msg_queue_size is not honored.
When using the subscribed property manager and a device is offline when calling twApi_PushSubscribedProperties(), the property values are written to a persisted file named subscribed_props.bin. The size of the file should be limited by the variable twcfg.offline_msg_queue_size. However, the actual file will grow considerably larger than the value specified by twcfg.offline_msg_queue_size.
C SDK Version 1.4.1 
Issue
Applies to
Description
Issues Fixed in This Release
CSDK-743
C SDK, WS EMS 5.3.3
SPM’s most recent value cache never removes deleted properties.
The Subscribed Property Manager (SPM) retains the most recent value for all properties that it has detected whose push type is set to VALUE. This cache always retained the most recent VTQ for every property processed by the SPM, even after those properties were removed from the Thing on ThingWorx Platform or callbacks for the property were unregistered. This behavior continually increased the size of the cache. This issue is fixed in this release.
CSDK-802
C SDK, WS EMS 5.3.3
Multiple open tunnels can cause tunnel disconnections.
This release resolves this issue.
CSDK-856
C SDK, WS EMS 5.3.3
Add note to C SDK developer’s guide about tick resolution parameter for tunneling.
The C SDK developer’s guide has updates concerning tick resolution and running the C SDK on Windows-based operating systems.
Known Issue
CSDK-916
C SDK 1.4.x
C SDK v.1.4.x releases use axTLS v.2.1.2. These versions of the C SDK are unable to connect to SSL Tomcat servers that do not specify pathLenConstraint in their installed server certificate (which include PTC Cloud Services production instances of ThingWorx Platform). For information about the pathLenConstraint parameter, refer to RFC 5280, section 4.2.1.9..
IMPORTANT! This issue is present only when using axTLS builds of the C SDK v.1.4.x. OpenSSL-based C SDK builds do not experience this issue.
CSDK-115 (13373562)
C SDK
Size of the file limited by twcfg.offline_msg_queue_size is not honored.
When using the subscribed property manager and a device is offline when calling twApi_PushSubscribedProperties(), the property values are written to a persisted file named subscribed_props.bin. The size of the file should be limited by the variable twcfg.offline_msg_queue_size. However, the actual file will grow considerably larger than the value specified by twcfg.offline_msg_queue_size.
C SDK Version 1.4.0 
Issue
Applies tò
Description
New in This Release
CSDK-1
C SDK
Replace all InfoTable iterations using twList_Next() within the Subscribed Property Manager (SPM) with twList_forEach().
To improve performance of the Subscribed Property Manager (SPM), the iterations over infotables that previously used the twList_Next() function now use twList_foreach().
CSDK-245
C SDK
The C SDK now ships with CMake. The distribution bundle includes CMake files so that developers can use CMake to build their applications for their desired platforms. The ThingWorx Edge C SDK Developer’s Guide has been updated for this release to provide guidance for CMake.
NOTE: While the old makefiles are still in the distribution bundle, they are deprecated with this release.
CSDK-256 (formerly EDGE-2185)
C SDK
Implement Synchronized State Handler within the C SDK.
The C SDK now provides the ability to install handlers to notify developers when the getPropertySubscriptions() is being called on ThingWorx Platform in response to a notifyPropertyUpdates message. This mechanism works in a similar manner to the bind event handler.
CSDK-321
CSDK-
Add public twApi functions to get/set all configurable properties in the twcfg struct.
When compiling dynamic .exe’s/dll’s on Windows, the twcfg struct is accessible onlly to the core API. Therefore, external libraries could not access certain critical configuration members, such as offline message size. All members of twConfig.twcfg can be written by public twApi calls. Note that twApi has NOT changed.
CDSK-362 (formerly EDGE-506)
C SDK
Upgrade C SDK to use axTLS 2.1.2.
The updates to the most recent release of axTLS include security fixes. The C SDK distribution bundle includes this latest version. The C SDK has been tested to connect to an instance of ThingWorx platform using the default cipher suites used by Java 8 and Tomcat 8.0.36+.
CSDK-789
C SDK
Modify the push behavior of the Subscribed Property Manager (SPM) to be multithreaded.
To significantly improve performance the twApi_PushSubscribedPropertiesAsync function and its callback handling have been implemented. It is now possible for multiple calls to the UpdateSubscribedPropertyValues service to be outstanding at the same time. The new API is twApi_PushSubscribedPropertiesAsync(char * entityName, char forceConnect,PushSubscribedPropertiesAsyncCallback cb, void* userdata). For more information, refer to the Doxygen documentation for the C SDK.
Issues Fixed in This Release
CSDK-13
C SDK
Column order in DataShape generated via C API is not maintained in data sent to ThingWorx.
Column order is nOT guaranteed to be preserved in InfoTables. The Data Shape used to specify the InfoTable supports an ordinal aspect on fields. This aspect can be used at display time to render the fields in the correct order.
Note too that InforTables store field values by key, not index. Refer to the ThingWorx Edge C SDK Developer’s Guide for more information.
CSDK-14 (formerly EDGE-1964)
C SDK and .NET SDK (until other SDKs and WS EMS are built with C SDK 1.4.1)
The C SDK could not establish a secure WebSocket connection (WSS, SSL) to a ThingWorx server. when attempting to connect. This issue has applied to the C SDK 1.3.2 through 1.3.5, .NET SDK 5.6.2 through .5.6.5, WS EMS 5.3.2.x, and iOS SDK 1.0.
CAUSE: Versions of Apache Tomcat 8.0.34 and above have disabled RSA-based ciphers by default due to forward secrecy concerns. (refer to https://tomcat.apache.org/tomcat-8.0-doc/changelog.html for 8.0.35.). The axTLS libraries used by WS EMS, C SDK, .NET SDK, and iOS SDK supported two encryption ciphers: TLS_RSA_WITH_AES_256_CBC_SHA and TLS_RSA_WITH_AES_128_CBC_SHA. Any application that used SSL for Edge connections if the Tomcat server was upgraded to 8.0.35 or later may have been affected by this change to Tomcat.
With the upgrade to axTLS 2.1.2, this issue is resolved for the C SDK in this release.
* 
The WS EMS, .NET SDK, and iOS SDK have not been rebuilt with C SDK 1.4.0 at this time. To avoid the issue, make sure that you are using the C SDK 1.4.0. Otherwise, refer to the release notes for WS EMS, .NET SDK, or iOS SDK for workarounds.
CSDK-55
C SDK
C SDK rejecting multipart messages with more than 127 chunks.
The C SDK message handling code incorrectly parsed the chunk ID and chunk count from incoming multipart messages, causing the message handling code to reject the chunks and ultimately ignore the message.
This issue is fixed in this release.
CSDK-739
C SDK
Possible Deadlock in twList_foreach() Handler.
To avoid a possible deadlock in Linux, do NOT call twList_Remove from within a foreach handler.
CSDK-746
C SDK
Improper return code caused Subscribed Property Manager (SPM) to buffer infinite records while offline.
An improperly defined return code caused the SPM to report pushes that failed to either be published or persisted as "persisted", resetting the enqueued count and allowing the SPM's VQT buffer to grow indefinitely.
This issue is fixed in this release.
CSDK-748
C SDK
Subscribed Property Manager (SPM) — most recent value cache only compared property name.
The SPM retains a list of the most recent value of every property with the push type “VALUE” that has been sent in so that it can compare the next value it receives against the last. When doing lookups in this cache, the SPM compares only the property names (remote edge names), not the entity names. If two bound Things have properties with the same name, they share a most recent value cache.
This issue is fixed in this release. The SPM compares the Thing Name as well as the property names when doing lookups in the cache.
CSDK-749
C SDK
Subscribed Property Manager (SPM) — most recent value cache iteration uses twList_Next.
The SPM uses a single twList containing references to the most recent value for every property of push type “VALUE” that the SDK has detected since initialization. Previously, as each VQT came in, a linear search was run on this cache for a property whose property name matched the incoming VQT’s property name (refer to CSDK-748). This iteration was performed using twList_Next, which was quadratic in complexity. This list can grow to contain many properties at runtime. This search method adversely affected performance when a list grew.
This release resolves this issue. The function twList_foreach is now used instead of twList_Next to search for matches. In addition, the search also compares the Thing Name associated with the incoming property name to the Thing Name associated with the property in the cache..
CSDK-750
C SDK
SetPropertyVTQ returns CHANGE_BUFFER_FULL if property does not change by configured value.
The function twSubscribedPropsMgr_SetPropertyVTQ returns TW_PROPERTY_CHANGE_BUFFER_FULL if the passed VTQ is for a property with push type VALUE, and the new value in the VTQ does not exceed (oldValue + threshold). The same happens if the property is set to a push type of NEVER. The result was that the linking application determined that the SPM’s buffer was full and likely caused it to force a push before trying to re-enqueue the same value, which continued to fail in the same way.
This issue is fixed in this release. The SPM compares the Thing Name as well as the property names when doing lookups in the cache.
CSDK-780
CSDK-
subscribedPropertyUpdateTaskForEachHandler invokes listeners with bad arguments.
This issue is fixed in this release.
Known Issues
CSDK-916
C SDK
C SDK v.1.4.x releases use axTLS v.2.1.2. These versions of the C SDK are unable to connect to SSL Tomcat servers that do not specify pathLenConstraint in their installed server certificate (which include PTC Cloud Services production instances of ThingWorx Platform). For information about the pathLenConstraint parameter, refer to RFC 5280, section 4.2.1.9..
IMPORTANT! This issue is present only when using axTLS builds of the C SDK v.1.4.x. OpenSSL-based C SDK builds do not experience this issue.
CSDK-812
C SDK, .NET SDK
SPM is incompatible with RAM backed offline message store.
If the offline message store is not written to files, the SPM initialization fails to initialize the SPM structure’s persistedValues stream. When attempting to push properties when not connected, this issue leads to a persistence failure in the SPM.
WORKAROUND: Use the file type of offline message store.
CSDK-115 (13373562)
C SDK
Size of the file limited by twcfg.offline_msg_queue_size is not honored.
When using the subscribed property manager and a device is offline when calling twApi_PushSubscribedProperties(), the property values are written to a persisted file named subscribed_props.bin. The size of the file should be limited by the variable twcfg.offline_msg_queue_size. However, the actual file will grow considerably larger than the value specified by twcfg.offline_msg_queue_size.
C SDK Version 1.3.6 
C SDK Version 1.3.6
Issue
Applies to
Description
Issue Fixed in This Release
CSDK-785
C SDK, .NET SDK
Determine cause of incoming message queue filling up, which caused message to be discarded.
The SDK now cleans up registered properties and services if a BIND fails.
Known Issues
CSDK-812
C SDK, .NET SDK
SPM is incompatible with RAM backed offline message store.
If the offline message store is not written to files, the SPM initialization fails to initialize the SPM structure’s persistedValues stream. When attempting to push properties when not connected, this issue leads to a persistence failure in the SPM.
WORKAROUND: Use the file type of offline message store.
EDGE-1964
C SDK, .NET SDK, iOS SDK, and WS EMS
The Edge device (C SDK) cannot establish a secure WebSocket connection (WSS, SSL) to a ThingWorx server. The error appears as Error 0, Error initializing SSL connection, twWs_Connect: Error restarting socket. Error 0, and/or No compatible ciphers when a C SDK device attempts to connect. This issue applies to the C SDK 1.3.2 through 1.3.6, .NET SDK 5.6.2 through .5.6.5, WS EMS 5.3.2.x, and iOS SDK 1.0.
CAUSE: Versions of Apache Tomcat 8.0.35 and above have disabled RSA-based ciphers by default due to forward secrecy concerns. (refer to https://tomcat.apache.org/tomcat-8.0-doc/changelog.html for 8.0.34.). The axTLS libraries used by WS EMS, C SDK, .NET SDK, and iOS SDK support two encryption ciphers: TLS_RSA_WITH_AES_256_CBC_SHA and TLS_RSA_WITH_AES_128_CBC_SHA. Any application that uses SSL for Edge connections if the Tomcat server is upgraded to 8.0.35 or later may be affected by this change to Tomcat.
WORKAROUNDS:
Downgrade to a version of Tomcat version 8.0.33 or lower.
In the server.xml configuration file of Tomcat, explicitly define a list of ciphers that includes the axTLS ciphers. For an example with a list of ciphers supported in Tomcat version 8.0.36, refer to https://support.ptc.com/appserver/cs/view/solution.jsp?n=CS245522.
* 
Make sure that any ciphers you use have been validated with any internal security requirements before implementing this workaround in production environment
C SDK Version 1.3.5 
C SDK Version 1.3.5
Issue
Applies to
Description
Issue Fixed in This Release
CSDK-755
C SDK and WS EMS
twTlsClient_Create could cause a segfault if multiple threads each tried to create a TLS client at nearly the same time. This issue appeared in the ThingWorx WebSocket—based Edge MicroServer (WS EMS), where communication between the WS EMS and Lua Script Resource could resulted in the creation of multiple HttpClient objects, each of which ran on its own thread and tried to create a twTlsClient. When two threads try to create a new twTlsClient, they could both call into SSL_library_init(), which caused heap corruption and a crash inside OpenSSL.
CSDK-129
C SDK and WS EMS
If a multipart response was received by the edge device, and that response arrived after its corresponding request had timed out, the final chunk of that multipart response is freed twice and the reconstituted message is leaked.
Enhancement in This Release
CSDK-745
C SDK and WS EMS
The C SDK now exposes the tunnelServiceCallback function so that clients can use the tunnel services that are implemented in twTunnelManager.c.
Known Issues
CSDK-812
C SDK, .NET SDK
SPM is incompatible with RAM backed offline message store.
If the offline message store is not written to files, the SPM initialization fails to initialize the SPM structure’s persistedValues stream. When attempting to push properties when not connected, this issue leads to a persistence failure in the SPM.
WORKAROUND: Use the file type of offline message store.
EDGE -1964 / CSDK-14
C SDK, .NET SDK, iOS SDK, and WS EMS
The Edge device (C SDK) cannot establish a secure WebSocket connection (WSS, SSL) to a ThingWorx server. The error appears as Error 0, Error initializing SSL connection, twWs_Connect: Error restarting socket. Error 0, and/or No compatible ciphers when a C SDK device attempts to connect. This issue applies to the C SDK 1.3.2 through 1.3.5, .NET SDK 5.6.2 through .5.6.4, WS EMS 5.3.2.x, and iOS SDK 1.0.
CAUSE: Versions of Apache Tomcat 8.0.35 and above have disabled RSA-based ciphers by default due to forward secrecy concerns. (refer to https://tomcat.apache.org/tomcat-8.0-doc/changelog.html for 8.0.34.). The axTLS libraries used by WS EMS, C SDK, .NET SDK, and iOS SDK support two encryption ciphers: TLS_RSA_WITH_AES_256_CBC_SHA and TLS_RSA_WITH_AES_128_CBC_SHA. Any application that uses SSL for Edge connections if the Tomcat server is upgraded to 8.0.35 or later may be affected by this change to Tomcat.
WORKAROUNDS:
Downgrade to a version of Tomcat version 8.0.33 or lower.
In the server.xml configuration file of Tomcat, explicitly define a list of ciphers that includes the axTLS ciphers. For an example with a list of ciphers supported in Tomcat version 8.0.36, refer to https://support.ptc.com/appserver/cs/view/solution.jsp?n=CS245522.
* 
Make sure that any ciphers you use have been validated with any internal security requirements before implementing this workaround in production environment
C SDK Version 1.3.4 
C SDK Version 1.3.4
Issue
Applies to
Description
Issues Fixed in This Release
EDGE-2127
C SDK 1.3.4
After pulling out the network cable from a device, C SDK 1.3.2 using OpenSSL hangs in SSL_write (for OpenSSL connection) until the cable is plugged back in. (64–bit Debian Linux)
This hang occurred consistently when sending the second chunk of a multipart message.
This issue is fixed in this release.
EDGE-2137
C SDK 1.3.4 and .NET SDK 5.6.4
When the C SDK tries to send offline_msgs.bin, no properties are logged on ThingWorx Platform.
This issue has been fixed in this release.
EDGE-2138
C SDK1.3.4
In C SDK 1.3.3, the C SDK leaks memory in twMap_Create().
This issue appeared when calling twMapGetDeleteFunctionMap and twMapGetParseFunctionMap in items that were being created in twMap.
This issue is fixed in this release.
EDGE-2140
C SDK 1.3.4 and .NET SDK 5.6.4
The SteamSensor example segfaults when yanking Ethernet cable.
The fix for EDGE-2137 also fixed this issue in this release.
EDGE-2157
C SDK 1.3.4, .NET SDK 5.6.4
Remove registration of NotifyPropertyUpdate handler in twApi_BindThingWithoutDefaultServices.
The .NET SDK uses the function, twApi_BindThingWithoutDefaultServices, internally.
* 
Do NOT use twApi_BindThingWithoutDefaultServices for C SDK development. It will not register handlers for GetMetadata or NotifyPropertyUpdate. As a result, it will not properly bind Things to ThingWorx Platform.
NSDK-22
C SDK 1.3.4 and .NET SDK 5.6.4
.NET SDK has an error and crashed without error message in log file
The issue was in the C SDK that is the foundation for the .NET SDK. The C SDK has the fix for this issue, and the new C SDK libraries are included with the .NET SDK so that it too has the fix.
Known Issue
EDGE -1964 / CSDK-14
C SDK, .NET SDK, iOS SDK, and WS EMS
The Edge device (C SDK) cannot establish a secure WebSocket connection (WSS, SSL) to a ThingWorx server. The error appears as Error 0, Error initializing SSL connection, twWs_Connect: Error restarting socket. Error 0, and/or No compatible ciphers when a C SDK device attempts to connect. This issue applies to the C SDK 1.3.2 through 1.3.4, .NET SDK 5.6.2 through .5.6.4, WS EMS 5.3.2, and iOS SDK 1.0.
CAUSE: Versions of Apache Tomcat 8.0.35 and above have disabled RSA-based ciphers by default due to forward secrecy concerns. (refer to https://tomcat.apache.org/tomcat-8.0-doc/changelog.html for 8.0.34.). The axTLS libraries used by WS EMS, C SDK, .NET SDK, and iOS SDK support two encryption ciphers: TLS_RSA_WITH_AES_256_CBC_SHA and TLS_RSA_WITH_AES_128_CBC_SHA. Any application that uses SSL for Edge connections if the Tomcat server is upgraded to 8.0.35 or later may be affected by this change to Tomcat.
WORKAROUNDS:
Downgrade to a version of Tomcat version 8.0.33 or lower.
In the server.xml configuration file of Tomcat, explicitly define a list of ciphers that includes the axTLS ciphers. For an example with a list of ciphers supported in Tomcat version 8.0.36, refer to https://support.ptc.com/appserver/cs/view/solution.jsp?n=CS245522.
* 
Make sure that any ciphers you use have been validated with any internal security requirements before implementing this workaround in production environment
C SDK Version 1.3.3 
C SDK Version 1.3.3
Issue
Applies to
Description
New in This Release
EDGE-2025
C SDK, .NET SDK
Add bind message splitting.
The bulk binding feature could cause the SDK to attempt to send a message that is larger than the configured maximum message size. When building the bind message, the SDK monitors the message size and returns an error when the message is full. When this error message is detected, the SDK sends the current message and starts a new one.
EDGE-1977
C SDK
Support libcfu as an implementation of twMap
EDGE-1900, EDGE-2044
C SDK
Add ForEach iterator function to twList API.
To all list iterations to be performed faster and in a thread-safe manner, the twList_Foreach iterator function has been added to twList API for this release. The twList_Next significantly impacts performance and has been deprecated in favor or twList_Foreach. It has been replaced in the following source files: twApi.c, twInfoTable.c, twTunneling.c, twFileManager.c, twMessaging.c, twSubscribedProps.c, list.c, twFileTransferCallbacks.c, twHttpProxy.c, and logger.c.
EDGE-2005,
C SDK
Replace twList with twMap in identified places.
To improve the performance of the C SDK, certain uses of twList have been replaced with twMap.
EDGE-1758,
C SDK
Provide a List-backed twMap forC SDK.
For this release, a list-backed twMap and twDict have been added. You can select the implementation you wan to use at compiled time. Note that map references should use a type of twMap.
EDGE-1653
C SDK, .NET SDK
To allow bulk binding in the C SDK and derived SDKs the twApi_BindThings function has been added for this release.
Issues Fixed in This Release
EDGE-1870
C SDK
Leak in twSubscribedPropsMgr_SetPropertyVTQ when the property is unknown.
If a VTQ is passed to twSubscribedPropsMgrVTQ after the property for which it is intended has been removed, the function leaks a twSubscribedProperty.
This issue is fixed in this release.
EDGE-1834
C SDK
O(n^2) performance degradation when retrieving parameters from tables with large row counts
When retrieving parameters from an infotable (for example, as input to a service), performance degrades exponentially as the number of rows in the table grows.
To resolve this issue, the twList_Next() function has been replaced with direct locking and iteration (twList_GetByIndex()), significantly improving perfornance.
EDGE- 1737
C SDK
twApi_SetSubscribedPropertyVTQ returns success when the internal buffer of the SDK is full and the VTQ is going to be ignored.
In twSubscribedProps.c, an error condition was logged and memory was cleaned up. However, the function returned success, which did not reflect the fact that the update exceeded the queue size and therefore was not actually sent. A return code has been added so that the queue can be flushed immediately (with twApi_PushSubscribedProperties) and resubmitted.
EDGE-1736
C SDK
Double free of a multi-part response chunk if the request times out.
If a multi-part response was received by the edge device, and that response arrived after its corresponding request timed out, the final chunk of that response was freed twice, and the reconstituted message was leaked.
This issue is fixed in this release.
EDGE-1735
C SDK
The function, twDataShapeEntry_CreateFromStream() can corrupt the stream if it encounters an entry with an aspect.
This issue is fixed in this release.
EDGE-1690
C SDK
twSubscribedProps.c leaks memory in some situations.
When the offline message store was compiled out, the edge application was not connected and was not forcing the SDK to attempt a connection.
This issue is fixed in this release.
EDGE-1647
C SDK
C SDK leaks memory while handling services if there is no output Data Shape present.
If a service was defined without an output shape (returns noThing), a memory leak could occur when creating a JSON object to store an aspect on twApi. When the output Data Shape exists, the associated aspect memory is cleaned up. However, when the shape does not exist, the aspect JSON object is created, never populated, and never cleaned up.
This issue is fixed in this release.
EDGE-1568
C SDK
WS EMS
twInfoTable_CreateFromJson leaks memory in certain cases.
This switch block in twInfoTable_CreateFromJson was missing break statements, which caused primitives to be created and abandoned for certain base types.
This issue is fixed in this release.
EDGE-630
C SDK
Data lost with offline storage when network disconnects.
This issue is fixed in this release. Offline message store is automatically initialized by twApi_Initialize(), so you do not need to initialize it separately. However, if your application has complex requirements, you can use the offline message store singleton that was added for this release, twOfflineMsgStore_Initialize() to initialize it separately. The singleton enables or disables offline message storage, passes in the maximum size of the store, and the path to the location of the offline message store. This function has no dependencies from twApi and twMessage in case OFFLINE_MSG_STORE is undefined.
This release provides three additional functions for offline message storage:
twOfflineMsgStore_SetDir()
twOfflineMsgStore_Delete()
twOfflineMsgStore_HandleRequest()
Refer to the files of the C SDK installation, /src/twUtils/twOfflineMsgStore.hand /src/twUtils/twOfflineMsgStore.c, for definitions and implementation of these functions.
The subscribed property manager has been decoupled from offline message store. Dependencies for Linux and Windows have been resolved.
Known Issue
EDGE -1964 / CSDK-14
C SDK, .NET SDK, iOS SDK, and WS EMS
The Edge device (C SDK) cannot establish a secure WebSocket connection (WSS, SSL) to a ThingWorx server. The error appears as Error 0, Error initializing SSL connection, twWs_Connect: Error restarting socket. Error 0, and/or No compatible ciphers when a C SDK device attempts to connect. This issue applies to the C SDK 1.3.2 and 1.3.3, .NET SDK 5.6.2 and .5.6.3, WS EMS 5.3.2, and iOS SDK 1.0.
CAUSE: Versions of Apache Tomcat 8.0.35 and above have disabled RSA-based ciphers by default due to forward secrecy concerns. (refer to https://tomcat.apache.org/tomcat-8.0-doc/changelog.html for 8.0.34.). The axTLS libraries used by WS EMS, C SDK, .NET SDK, and iOS SDK support two encryption ciphers: TLS_RSA_WITH_AES_256_CBC_SHA and TLS_RSA_WITH_AES_128_CBC_SHA. Any application that uses SSL for Edge connections if the Tomcat server is upgraded to 8.0.35 or later may be affected by this change to Tomcat.
WORKAROUNDS:
Downgrade to a version of Tomcat version 8.0.33 or lower.
In the server.xml configuration file of Tomcat, explicitly define a list of ciphers that includes the axTLS ciphers. For an example with a list of ciphers supported in Tomcat version 8.0.36, refer to https://support.ptc.com/appserver/cs/view/solution.jsp?n=CS245522.
* 
Make sure that any ciphers you use have been validated with any internal security requirements before implementing this workaround in production environment
C SDK Version 1.3.2 
C SDK Version 1.3.2
Issues Fixed
ID
Applies to
Description
EDGE-758
C SDK and WS EMS
When calling the GetRemoteMetadata service from the ThingWorx platform via a Connection Server (v.6.5.11, 7.0, and 7.0.1), the Connection Server logs an error and the ThingWorx platform service times out. The WS EMS is successfully receiving the request and sending packets back to the Connection Server.
This issue is fixed in this release.
EDGE-874
C SDK and WS EMS
The WS EMS was responding very slowly to requests, in comparison to v.5.2.2 and 5.3.0.
This issue is fixed in this release.
EDGE-996
C SDK
twFileManager_SendFile() stopped sending files.
This issue is resolved.
EDGE-1046
C SDK
File transfer that use identifiers were not working with the C SDK.
This issue is fixed in this release.
EDGE-1074
C SDK
Some C SDK functions do not return TW_OK on success
The documentation for the functions (Doxygen output bundled with the C SDK) has been updated for this release. The updated doc is also in the ThingWorx Edge Help Center.
EDGE-1087
C SDK
C SDK crashed when the SSL layer was disabled.
This issue is fixed in this release.
EDGE-1125
C SDK
The C SDK code causes a crash at twApi_Delete() function and the application stops.
This issue is fixed in this release.
EDGE-1297
C SDK
String property does not push changes if Composer pushType is not set to Always.
This issue is fixed in this release.
EDGE-1432
C SDK
C SDK twDirectory_MoveFile should perform a copy and delete instead of a rename.
RESOLUTION: The twDirectory_MoveFile method now attempts a rename. Then, if the rename fails, it copies the file to the destination and deletes the file from the source.
EDGE-1453
C SDK
Implement logic in twFinishFileTransfer to search the openFile list using the adjustedPath if the tid search fails.
This issue is fixed in this release.
EDGE-1484
C SDK
File Transfers with Identifiers > 1 Block Size have the potential to not clean up a file (ThingName Based)
This issue is fixed in this release.
Known Issue
EDGE -1964 / CSDK-14
C SDK, .NET SDK, iOS SDK, and WS EMS
The Edge device (C SDK) cannot establish a secure WebSocket connection (WSS, SSL) to a ThingWorx server. The error appears as Error 0, Error initializing SSL connection, twWs_Connect: Error restarting socket. Error 0, and/or No compatible ciphers when a C SDK device attempts to connect. This issue applies to the C SDK 1.3.2, .NET SDK 5.6.2, WS EMS 5.3.2., and iOS SDK 1.0.
CAUSE: Versions of Apache Tomcat 8.0.35 and above have disabled RSA-based ciphers by default due to forward secrecy concerns. (refer to https://tomcat.apache.org/tomcat-8.0-doc/changelog.html for 8.0.34.). The axTLS libraries used by WS EMS, C SDK, .NET SDK, and iOS SDK support two encryption ciphers: TLS_RSA_WITH_AES_256_CBC_SHA and TLS_RSA_WITH_AES_128_CBC_SHA. Any application that uses SSL for Edge connections if the Tomcat server is upgraded to 8.0.35 or later may be affected by this change to Tomcat.
WORKAROUNDS:
Downgrade to a version of Tomcat version 8.0.33 or lower.
In the server.xml configuration file of Tomcat, explicitly define a list of ciphers that includes the axTLS ciphers. For an example with a list of ciphers supported in Tomcat version 8.0.36, refer to https://support.ptc.com/appserver/cs/view/solution.jsp?n=CS245522.
* 
Make sure that any ciphers you use have been validated with any internal security requirements before implementing this workaround in production environment
C SDK Version 1.3.1 
C SDK Version 1.3.1
Issues Fixed
ID
Applies to
Description
EDGE-842
C SDK only
The Steam Sensor with OpenSSL example for Linux that is provided in the zip archive for the C SDK did not work without changes to the Makefile.
The OpenSSL libraries are now included in the distributed zip archive. The example should now compile "out of the box" from the distributed zip archive. If you have your own OpenSSL libraries, you can build against them as well.
EDGE-834
All SDKs and WS EMS
Pending requests to the ThingWorx Platform would time out if the edge device received a request from the ThingWorx Platform while it waited for the response.
Workaround: Increasing the message timeout from the default value of 10 seconds to 60 seconds and changing the port configuration resolves this issue.
EDGE-829
C SDK, .NET SDK, and WS EMS
The ListFiles service gives different result for WS EMS 5.3 and 5.0.
The ListFiles service in this release (5.3.1) now returns the path without the file name, as it did in release 5.0.
EDGE-827
C SDK
The Tunnel Manager was using “==” to compare strings. This release resolves this issue.
EDGE-823Case 12819599
C SDK and WS EMS
The WS EMS running as a service on a Netbiter ec350 device failed to start up and displayed the following message: Error creating BSD socket.
This release resolves this issue.
EDGE-683
All SDKs and WS EMS
An ADO application could not connect to the ThingWorx platform through an NTLM proxy server.
This issue is fixed in this release. Tunneling through an NTLM proxy server is working.
C SDK Version 1.2.0 
C SDK Version 1.2.0
New Features
Added support for subscribed properties.
Added support for aspects on service definitions.
Added functions for setting both the gateway name and the gateway type to the twWs struct.
Updated developer guide.
Added capability to clear proxy settings.
Removed dependency on Joyent HTTP parser.
SDK now has dependency on cJSON library (included in distribution).
Changed default socket read timeout to 500ms.
Bug Fixes
The following issues are resolved in this release:
The NoTls option will not compile on the C SDK.
All bound Things were registering with the same Thing Name.
GetDirectoryStructure was not including a leading / character on paths.
GetDirectoryStructure was not including virtual directory names as root directories in the result.
Fixed deadlock in multi part message init.
Timeout specified in twcfg.socket_read_timeoutis now passed into the socket read call.
Socket read timeouts no longer disconnect WebSocket.
C SDK Version 1.1.2 
C SDK Version 1.1.2
Version 1.1.2
New Features
API reference documentation now included in both the header files and as html in the doc/html directory.
New, updated developer guide.
Added support for registering events in the C SDK. Events can be browsed from the ThingWorx Platform.
Fix for occasional 'selecting on socket' error reported in logs.
OSX Makefile fixes.
C SDK Version 1.1.1 
C SDK Version 1.1.1
New Features
Added ability to change offline message store directory using twApi_SetOfflineMsgStoreDir.
Compile time settings are now readable in the twcfg structure.
Added OSX build files back into distribution.
Added GetDirectoryStructure service. This change is for backward compatibility only and is deprecated.
Added a SteamSensorWithMinimalFootprint example.
Modified SteamSensorWithMinimalFootprint to be single threaded.
Changed Linux build of SteamSensor to have logging enabled.
Bug Fixes
Fixed the incoming message handling that occurs within the sendMessageBlocking function to handle responses only. Avoids deadlocks in certain situations.
Changed twMessage_Send to check to refer to if we are authenticated before we send.
Changed code that sends offline messages to insert a new RequestId to remove any potential conflicts from a previous ID.
Added Mutex protection in twTlsClient_Reconnect and twTlsClient_ConnectSession.
Fixed segfault that occurs during non-persistent offline message storing.
Updated copyright in documentation.
Added registration of Location property so that it shows up when browsed.
C SDK Version 1.1.0 
C SDK Version 1.1.0
New Features
Support for transferring files and directories that have multi-byte characters in their names.
Support for browsing directories and files that have multi-byte characters in their names.
Support for tunneling.
Support for NTLM proxy servers.
Addition of a TLS wrapper to support OpenSSL/FIPS.
Portable multi-threading layer (use is optional).
SHA-256 certificate signature support.
Full certificate validation.
Run-time overriding of default values.
Wildcard property and service callback registration.
Authentication event callbacks.
Bind event callbacks.
Bug Fixes
EDGE-318: C SDK disconnects.
EDGE-291: Segfault on service call with empty input
EDGE-221: C SDK continues to try to reconnect after number of retries is exhausted.
EDGE-189: C SDK not checking for ping timeouts after sending a ping.
EDGE-188: Cannot correctly import services from the C SDK to the ThingWorx platform.
EDGE-169: C SDK does not reconnect after entire server shutdown.
CreateBinaryFile will now open/write/close if it is called without StartFileTransfer being called previously.
Fixed file transfer to support both 5.0 and later servers.
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