Commands that MUST be supported

[notator]

A Synth MUST support NOTE_ON, otherwise the host can't play anything.

A Synth MAY support NOTE_OFF. (If it doesn't, it MUST use zero velocity NOTE_ON.)
A Synth MAY support CONTROL_CHANGE. (If it doesn't, the sounds can't be changed.)
A Synth MAY support AFTERTOUCH.
A Synth MAY support PATCH_CHANGE
A Synth MAY support PITCHWHEEL

So there MUST be a commands declaration, and there MAY be a controls declaration.