If you alter signatures or data structures in the published header file, there is breakage. If you add new signatures or data structures, software compiled aga

If you alter signatures or data structures in the published header file, there is breakage. If you add new signatures or data structures, software compiled against the previous version should still work with the new version. In my opinion the whole issue is more important on Windows than on Linux. Just recompile the application against the new library or keep both the old and the new soversion around. Some Linux distributions go into major contortions to make ABI stability work, and still compiled applications that are supposed to work with newer distros crash. It is a waste of resources.