When I saw this coming, I didn't update GV IP. I'm still on 1.4.8. I can still make calls through GV IP as of this writing. I wrote GV IP's dev and he said that, while GV IP can no longer use the API, Google has not yet removed the service. This is why it still works.
Who knows how long it will take Google to actually remove the service, so for now, I'll stick with 1.4.8.