While I still consider Sketch's model leagues more customer-friendly than Adobe's, I'm not happy that they appear to have given up any attempt at meaningfully versioning the file format. I can completely understand something like an overhaul to the way symbols are handled breaking compatibility with older versions of the app, but when an update is adding things like a new color picker and tweaking vector snapping, it seems like a stretch that the previous version can no longer open files created by the latest one.