What is the minimum hardware supported by nv2 sync?

I tried to enable it on a few older 802.11g radios and I get an error that says this chipset is not supported. It is an RB600 with a 900MHz card based off of the AR5413 chipset.

What Mikrotik hardware is supported in AP mode for nv2 sync? I understand pretty much all client radios are as the AP handles the synchronization.

Find in mikrotik wiki...
https://wiki.mikrotik.com/wiki/Manual:Nv2

Nv2 is supported for Atheros 802.11n chips and legacy 802.11a/b/g chips starting from AR5212, but not supported on older AR5211 and AR5210 chips. This means that both - 11n and legacy devices can participate in the same network and it is not required to upgrade hardware to implement Nv2 in network.

AR5413 device could work only as a client and not as AP in nv2 sync mode. It is due to the lack of hardware feature support that is required for the sync.