If you update the Google Voice app, you cannot make phone calls anymore if you cannot randomly validate a US phone number. Which pretty much kills the only use case for googlevoice: having a phone number when traveling, when you cannot receive SMS on your US phone number (thanks verizon).
You can still call from the website, for now, but not the app.
There is a discussion on Hacker News, but feel free to comment here as well.
If you read the hacker news thread, this was just a misconfiguration of the user’s voice app. They needed to set prefer Wi-Fi calling and everything just worked