Basic Customization > Windchill Customization Basics > Managing Customizations > Best Practices for Customizing Files Supplied by PTC > Managing codebase Property Files > Manipulating Property Files
  
Manipulating Property Files
Most property files should be manipulated using the xconfmanager utility. The reason to use either of these tools is that they store the property values you set in the <Windchill>/site.xconf file. They then propagate those values to the proper *.properties files. (Comment blocks are placed at the top and bottom of *.properties files that the xconfmanager has updated.) If a PTC maintenance update delivers changes to properties that you have changed, the xconfmanager automatically propagates the property changes stored in your site.xconf file on top of the PTC updates.
In many cases, there is a one-to-one correspondence between an *.xconf file and its *.properties file; for example codebase/wt.properties.xconf and codebase/wt.properties. In other cases, there is not a matching XCONF file. Even without an associated XCONF file, a properties file can still be manipulated with the xconfmanager Utility.
The following codebase properties should not be manipulated with the xconfmanager Utility:
associationRegistry.properties
descendentRegistry.properties
modelRegistry.properties
moduleRegistry.properties
moduleDir.properties
debug.properties
This is because these properties contain properties not suitable for the xconfmanager Utility.
If there are a lot of new properties that you need to add to a file such as wt.properties, rather than using xconfmanager Utility to set each property, consider creating your own declarative XCONF file. In this file, you declare the properties with a targetFile of wt.properties. Then use xconfmanager Utility to install this file into the declarations.xconf file. For an example of creating a service provider property file, see Adding a Custom Service Provider Property File.