I've personally never had a painless Django upgrade (except for patch releases). I always seem to fall into that grey area where I'm relying on undocumented beh

I've personally never had a painless Django upgrade (except for patch releases). I always seem to fall into that grey area where I'm relying on undocumented behaviour of documented features (e.g. not using framework internals per se). I remember one Django release which changed the behaviour of views that returned files to download (it was probably Django 1.4), but there was no mention of that in the release notes. Sometimes I've knowingly relied on framework internals in ways I expected to eventually break, but those situations don't represent the bulk of my experience with painful upgrades.