This error appears during UPD when a build fails. The _ant_generatedb will fail within a few minutes with the following error - Ant property "targetVersion" not set.

This issue is because code generator has failed due to code generator files for the UPD you’re applying, hasn’t been updated properly in the build home. You will have to compare these two files:

\build_home\source\fndbas\zip\ifs-codegenerator.zip (copy and extract in your user folder location)

\build_home\build\IfsBuildTasks\developer.studio.libs

See if the version.txt has the version from latest UPD (from Archive) or does it have a different version applied from a hotfix. Then manually merge the correct file from Archive because the automatic merge in ISD tool will not merge the correct file.