This fixes a bug in #3634, and refines the logic so that the warning is only given if the incoming tiddler exists as a shadow tiddler. (In my case I have several draft core modules inactive in my notes wiki and they were erroneously suppressed from the upgrade).
Previous changes since 5.1.7 broke the documented semantics by no
longer returning true when the versions match. It affected the upgrade
process, making it impossible to upgrade to a later pre-release (ie
where the version numbers in the upgrade.html match those in the file
being upgraded).
Also reviewed and updated the calls to checkVersions.
@felixhayashi I think that this effectively reverts the change you
original submitted. Are you OK with it?
There are still some warnings about making functions in a loop, but
I’ll fix those as a separate pull request because the fixes are more
than typographic errors.
