Hello.

We only provide bugfixes or security fixes to the current version - if such fix is necessary, it is labeled as a new build of the same version.

There is never an API change inside the same version.

New versions (with feature upgrades) are generally backward compatible. We keep breaking changes to minimum, but cannot completely avoid them (but if they happen, they are usually in less-used parts, and the changes needed are trivial). All such changes are documented in the "What's New" document that comes with a new version - you can access those from kb.opclabs.com/Versions .

Best regards