Hi Guys,
I'm only guessing, but obviously the beta licence is specific to the MAC address, so probably not migrateable (is that a word?). As Keith says in his News post, the B+ units still run with original ADSB functionality and as the whole ethos of see, be seen and avoid relies on the P3i Bridge part, new licences are being sold (once the shop opens - hopefully soon!!) with either full kits or Bridges. In the meantime, I see Lee has provided a link on the Licensing and Downloads page for a 28 Day Demo Licence. I haven't tried it, but this might be the answer to getting your Pi2s going until Bridges are released. Worth a try and please post to let the rest of us know if it works (or not).
Regards
Peter