I started on Ember around the 1.12 timeframe and left that job about a month ago and we were on 2.6. There were a couple hiccups going to 2.x but nothing more

I started on Ember around the 1.12 timeframe and left that job about a month ago and we were on 2.6. There were a couple hiccups going to 2.x but nothing more extreme than I've experienced with any other major version update. The Ember team also does a stellar job providing useful deprecation notices and not breaking any minor version update, i.e. if you're on 2.1, you can upgrade directly to 2.6 and be reasonably confident it'll still work. Your console might get flooded with deprecation warnings, but they helpfully link to the release docs for the change. The only thing I'm not a huge fan of is their JSON-API as a default data adapter, since there's a ton of immature JSON-API server-side libraries with varying levels of spec compliance and completeness. If you're backed by Rails, you're in good shape. If you're backed by Java, you're fairly fucked.