Description
Mod Organizer 2 is a mod manager created by Tannin to support 64bit games like Skyrim Special Edition and Fallout 4 in addition to all the 32bit games MO1 already supported. Tannin discontinued the project when he was hired by the Nexus team to develop their new Vortex mod manager.
MO2 was not completed and was left with many issues. LePresidente managed to fix it to a usable state by himself after SkyrimSE came out, adding support for it, and releasing v2.0.8.
The project took up speed again after a few more coders showed up in late 2017, and an incredible amount of work has been done!
There are many MRC resources related to MO2 which include guides and tutorials on using it. This is a list of resources tagged with MO2
The latest version for Starfield modding, is 2.5.0 RC2 (Release Candidate), which can be download from their GitHub repository.
Support
Support for Mod Organizer 2 (MO2) can be found on thier Discord server; the invite and channel links are included in the MRC resource.
Updates
For version 2.5.0, the installer will wipe any third party plugins as very few from 2.4.4 will be compatible with 2.5.0. If you've already installed a 2.5.0 beta build, I'd recommend simply overwriting the files using the archive download.
For older MO2 versions, a clean install is highly recommended if you do not use the installer as leftover files from 2.4.4 can and will break parts of 2.5.0 in addition to leaving old, extraneous files in the MO2 directory. You can migrate old portable instances by copying the mods, downloads, profiles, overwrite directories and modorganizer.ini file to the new install. If you use any third party game plugins, it is highly recommended to wait for an update before loading those instances.