After changing the version of an issue from D7 to D6, DrupalCI applies the D6 patch to D7 and and tests against D7:
https://www.drupal.org/node/2629392#comment-10680648
A more detailed example #2637810: D6 patch testing issue shows how changing the "Version" of the issue isn't respected by DrupalCI - DrupalCI tests against the old version, not the new.
This seems related to #2635822: Patches untested when issue status not explicitly changed to "needs review", where changing status to "Needs review" does not trigger DrupalCI to test the patch.
Comments
Comment #2
tr commentedComment #3
MixologicMoving to pift queue.
Comment #4
drumm#2667338: Update file's version for testing when issue's version is selected