RMG v0.3.9 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 "Don't check for updates again" checkbox appearing when requesting an update check through Help -> Check For Updates
Add game format, file name, file extension, file size, game I.D. and game region columns to the list view of the ROM browser which can be toggled in the "Show/Hide Columns" menu of the context menu in the list view of the ROM browser (thank you @RetraCarteR)
Add "Reset Column Sizes" to context menu of the list view of the ROM browser (thank you @RetraCarteR)
Add "Analog Stick Sensitivity" setting to RMG-Input (thank you @JaxonWasTaken)
Add "Save Filename Format" setting to the Core tab of the settings dialog (see mupen64plus/mupen64plus-core#998)
Add "Edit Game Input Settings" to the context menu of the ROM browser
Add support for 7z files
Add progress status to the loading screen in the ROM browser when loading takes more than 5 seconds

Download: RMG v0.3.9
Source:Here