Have an older SKD PIG plate carrier.
Got this to modify,,fits the Velcro flap.
skdtac.com
There's a Condor retrofit,,I have no experience with.
The Condor RS cummerbund retro kit upgrades your current plate carrier with our highly popular rapid release system. Seamlessly integrates with carriers that utilize hook and loop flap system, the Retro Kit also features soft armor pockets that are compatible with the Condor VAS side plate.