@elextr well, I rather see that as a plain bug, and I'm not sure we really want bug-for-bug compatibility… and here all that I can see as incompatible behavior is that now plugins would know that a file is *not* saved when quitting, which is basically giving it more, or at least correct, information. I fail to see any case that was correct but would be compromised because of getting correct information on this; if anything it would introduce different behavior because the code *explicitly wanted to perform different actions depending on the saved state* but was lied to, and thus only likely to perform incorrectly in the first place.
And in any case, we broke ABI in this release (3fa7576e13e129900a6e0acbd5460237f9a1b614), would that be enough for you?