This Module is currently available.
FSFX's older version of Mutable Instruments Rings set to not need a +5v rail
The older revision of the FSFX 107 has a jumper to select the "Digital Voltage Source", either the +5v or +15v rail. This version in ModularGrid is for the jumper set to +15.
I believe in newer version of the module eliminates this jumper and I don't know if it uses the +5v rail or not.
These merchants probably sell this module. Huh?