We just upgraded from 12.8 to 13.5 and now all our installers fail because of a missing backslash between the APPDIR and subdirectories behind it.
All the path handling was done (5 years ago) with "[APPDIR]mySubDir" where a backslash had always been appended to APPDIR.
Has that behavior been changed? I do not believe anything else in our .aip project was changed to cause this.