Considering the current numbering scheme, 0.9 will be the unstable version of 1.0. Which means 0.9 should give us a very good idea of the final backwards compatible API (hopefully)

Or it might be the unstable version of 0.10.

The dots are there for a reason.

IMHO, it should be followed by 0.12, because 0.10 is too confusable with 0.1, but 0.12 is clearly a new version...

They use a variation on semantic versioning, which is pretty standard:

    major.minor.revision

revision is incremented when backwards compatible bug fixes are added

minor is incremented when backwards compatible features are added

major is incremented when backwards incompatible change is introduced.

All of them are integers, and the smaller ones are reset to 0 when a bigger one is incremented.

For versions 0.x.x (pre v1), backwards incompatible changes are allowed at any time.

There are more rules, see http://semver.org/

imo next version will be 1.0 because they are on the fast releasing period

Possibly, I'm just commenting on the logic that 0.9 is followed by 1.0 (or 1.9 by 2.0, if you want).

Streams are everywhere, as an abstraction of async I/O model. Hope the Stream API will have a cleanup by 1.0.

Might be smart to mention in the title that its just an unstable release.

every odd version is unstable

you are right

Nothing jumps out at me as significant to bump the version to 0.9. Can someone explain what makes certain changes worthy of the version change?

Node follows a even/odd version scheme where even releases are stable and odd releases are unstable. v0.9.0 is just the first release of the unstable v0.9 series.

The versioning scheme is unfortunate because it confuses people. After Node 1.0 we'll switch a less confusing version system.

Is it not standard semver? What will node switch to?

isaac likes semver - so probably that

I haven't even finalized migrating from 0.4 to 0.8...