[donpark]

With node and similar projects, notion of stable/unstable is closer to geological notions (earthquake) and applies more to version branches (continents) than individual releases (states).

0.4 branch is and should be stable, meaning we can build on it and they'll try not to make big changes that could break what you built.

0.5 branch is unstable in the sense anything could change, even features added in 0.4 or older although they'll need compelling reasons to do that.