How do I warn users after I changed the build state version or the index file version?
Changing the build state version org.eclipse.jdt.internal.core.builder.State#VERSION will cause a full build when the user restarts the workspace with the new version. As well changing the index file version org.eclipse.jdt.internal.core.index.DiskIndex#SIGNATURE will cause all files in the workspace to be reindexed when the user restarts the workspace with the new version. In both case, you should add an entry in the build notes in the “What’s new” section so that users are aware of this change.