Thanks to some dedicated work by qwertymodo, Snes9x 1.55 now has MSU-1 support, including the MSU-1 distribution pack. The MSU-1 is an SNES expansion chip invented by byuu (author of higan), you can find some more information about it here. LuigiBlood also did some work on increasing the BS-X Satellaview support.
Tmkk kindly provided a macOS build, so mac users should finally be able to upgrade.
Other than that there are some game fixes and housekeeping work.

Changelog:



- Added support for the MSU-1 coprocessor. (qwertymodo)
- Added support for MSU-1 distribution pack. (qwertymodo)
- Added support for BS-X Satellaview memory packs and data (LuigiBlood)
files.
- Improved BS-X memory mapping accuracy. (LuigiBlood)
- Fixed APU error causing issues with some games. (byuu, qwertymodo)
- Added option to ignore patch checksums. (qwertymodo)
- Fixed build warnings / undefined behavior. (bonimy)
- Correct pixel placement in hires. (BearOso, OV2)
- Fixed RAM mapping for Light Fantasy. (hex_usr, BearOso)
- Added Circuit USA APU timing hack. (BearOso)
- libretro: Merged some changes from downstream repository. (OV2)
- GTK+: Allow use of XDG config directory. (BearOso)
- GTK+: Add 10th save slot. (Yama****aRen)
- GTK+: Updated Spanish translation. (jristz)
- Win32: Switched to Studio 2017. (OV2)
- Win32: Fixed problems when minimized in d3d. (OV2)
- Win32: Split Patch/Rom directory. (OV2)
- Win32: Simplified compilation by removing or including
some dependencies (included CG headers, completely
removed FMOD and FMOD_EX, moved direct draw to compile
switch) and reworking solution/configurations. (bonimy, OV2)
- Win32: Fixed crash with movie dialog (OV2)
- Win32: Changed hotplugging (OV2)
For: Windows, and macOS

Download mirrors:

https://sites.google.com/site/bearoso/
http://www.s9x-w32.de/dl/