There have (so far) been sixteen named updates after the game's initial release.
Each major release has been specifically named & given a number of it's own e.g. 2.3 Living Ship.
The Bytebeat Update Patch is not included in these; despite being a content update that also changed & improved a lot of the game's systems.
The Experimental Branch on Steam is a version of the game that is updated earlier than anywhere else; for the purposes of testing the game & ironing out any kinks, bugs & crashes caused by the changes made by the update or patch; prior to release to the rest of the general public. You can opt in to this (or out at any time) via Steam. Always create backups of your save first; just in case something goes wrong.