The latest official firmware release is 1.2.0. The latest BETA release is 1.4.9, but it is still under development and found here:https://forum.sequential.com/index.php/topic,1190.0.htmlAnd yes you can use SysEx Librarian (that's what I use on my Mac).
There's nothing essential in the beta, mainly some minor bug fixes. They also introduced some LED issues with the beta, so personally I'm waiting until the official update comes out.