I've never had to change anything between upgrades (aside from changing deprecated stuff). Are you referring to the jump between from 0.7 to 0.10 a few years ago or have you had more recent issues?

Yeah, I just went and had a look at the project in question and I'm being unfair to SBT, it was a plugin I use to package WARs that changed underneath me. The plugin was quite closely coupled to the version of SBT, but the latest variant of it (once I found out about the migration to a different artefact) seems good.