RMG v0.5.1 is released. Rosalie's Mupen GUI is a free and open-source mupen64plus GUI written in C++. It offers a simple-to-use user interface.

RMG changelog:
Fix window title of the windows installer
Fix video plugins which use vulkan not working on some Linux distributions
Fix 'Edit Game Input Settings' not saving settings when changing certain settings
Fix crash when having the RMG-Input configuration GUI open and closing RMG with control+c on Linux
Fix 'open_rom(): not a valid ROM image' error showing up sometimes when launching RMG with a ROM specified on the commandline
Update mupen64plus-core, GLideN64, paraLLEl and SDL_GameControllerDB

Download: RMG v0.5.1
Source:Here