Hello olajeffb,

The dev edition of Firefox receives frequent updates, which usually follow the release cycle of the beta channel. You can find a release calendar for beta and dev editions here: https://whattrainisitnow.com/release/?version=beta I hope this answer is helpful.

The Developers Edition is basically the same as Beta channel but with additional developer features.

There can usually be nine builds in testing a version on Beta channel though it used to be as many as fourteen.

There were nine beta builds of Firefox 144.0 and it is currently at 1Firefox 45.0b4 for the Firefox 145.0 Beta.