It’s all case-by-case. You need to know the details of each program from a Vsig perspective. Programs developed with version 5-exclusive modules (modules made available after version 3) will not work – due to lack of code and/or memory.
Examples:
e.g. DISTORT, C_DTIMER (global tempo), ADSR modules were added starting in version 3, so would not work on a DSP4000 or an 7000/orville running modules v2.7 or v2.2
e.g. DIFFCHORUS module: available on all versions (DSP4000, 7000, H8000)
N.B. But keep in mind modules from different firmware versions, may have been updated/fixed to have bugs removed, etc…