プロジェクトで2.0.xバージョンを使用していますが、最近、マスターブランチのみをサポートするバンドルが増え始めています。
マスターブランチに移行する必要がありますか?
It's not stable and may contain unfinished code. Also, there are a lot of break changes that haven't been documented yet. If you're starting a new project, then go for master, if you have already written some code, I'd better wait for the next 2.1 release (all bundles should support it).
Most popular bundles work with 2.0 too, but you must often use the branch for your symfony version, not a bundle's master branch.