FOSS gamedev and creative worlds

The Minetest server I play on uses the stable build of Minetest (as of this writing, v0.4.4).

For play on on hard drive, I download and compile (linux) the latest unstable builds (as of this writing, v0.4.4-d1).

Are the unstable builds compatible with the stable builds of the same version?

I don't want to test this on my online account for fear of messing up that account in some way.

I'm asking more out of curiosity than neccessity since I have enough hard drive space to run the stable version for my online play and have the latest unstable version for local play.

Thanks.

Should work.
There were no changes to the registration thing, so you dont have to fear anything.

Would it work if the server was the unstable dev version and the client was stable