Hi Bithov, we *do* care a lot about backward compatibility*.
We cannot make a strong commitment for contributed libraries and external ones, though, otherwise Org would not evolve. org-drill.el was removed from the contrib/ directory 1 year ago: https://code.orgmode.org/bzg/org-mode/commit/2c8e8b4a Perhaps you can try to find someone who wants to maintain it. * https://bzg.fr/en/the-software-maintainers-pledge/ -- Bastien
