If this really works, it is what Nothing's partnership with Sunbird claimed to do (and lied about) a couple weeks ago - before being called out and shut down
It looks like Beeper has actually managed to do the latter, which is really exciting!!
There is a great blog post by JJTech (author of the pypush library, tech Beeper Mini is based on) also on the front page right now: https://news.ycombinator.com/item?id=38532167