I saw it on the MMDVM mailing list, which is on Yahoogroups. It's to do with UDP loss in recent Linux kernels.
Subject contains "Re: MMDVM/BM Loss"
I don't have a web link as I receive the list via email.
They have done so if you use the mmdvmhat firmware for things like Jumbospot, Zumspot, DVMega etc. which use Andy CA6JAU's modem code.
You would need to substitute a dual band WiFi module, the effort of supporting WiFi is way beyond the resources available to SharkRF which is why they use a module in the first place. The WiFi firmware would deal with the band-switching as necessary.