Version 1.1.7 of Submarine is now out.
EN-104 is a Quad envelope generator designed to complement the PO-204 for 4-op FM synthesis. It’s offers 4 fast but simplistic ADSR envelopes with a single shared trigger and gate. Also a built in linear VCA. The AR, DR, SL, RR and VCA Attenuation for each of the 4 envelopes is controllable via Knobs AND CV.
If you want to change the FM algorithm on the fly, use the new Algomorph from Delexander
If you want operators that actually sound nice, use something from @Squinky