> If the code is compatible with 2.6+ only, the “2.5” Trove classifier should not be used.  (Maybe I’m misunderstanding your point.)

I was referring to your comment about the X in X.Y.Z. We also need to bear in mind that you sometimes just get trove classifiers ending in ":: Python :: 2", with no more specific version information. (Of course, there can be a check for this, with perhaps an installation-time warning.)