I was going from SFP+ to SFP28. Not sure about SFP to SFP28. But with that EEPROM change you could also try going from SFP to SFP+, just use different bandwidth values.

You could also try resoldering new/thicker Twinax wires to old SFP connectors and update the EEPROM. My soldering skills apparently aren't that great. If yours are or you have plenty of old connectors you should give that a try.