Personnalisation de base > Windchill Customization Basics > Managing Customizations > Best Practices for Customizing Files Supplied by PTC > Managing codebase/{wtcore,netmarkets,pdmlink} Files
  
Managing codebase/{wtcore,netmarkets,pdmlink} Files
If you have a requirement to modify any of the files, such as JSP files, under the <Windchill>/codebase/wtcore, <Windchill>/codebase/netmarkets, or <Windchill>/codebase/pdmlink directories, be aware that during a maintenance installation the PTC updates to the same files could overwrite your changes.
To prevent overwriting, you should utilize the safe area procedures as described in Setting Up a Directory Structure for Managing Customized Files and Text Tailoring.
Best Practices for Customizing Files Supplied by PTC