Eryk

That having been said, once upon a time I did install WhatsApp on an old phone that I no longer care about. I just upgraded the app and it seems to work, but I have no idea how to join the group that you invited me to.

So thank you for the invitation. Let me know when the group is looking for a chat. I'll fire up this old phone and we'll get to work. Thanks!

You can just use whatsapp web! web.whatsapp.com no application required. The group is actually really active, that's the technology group, the general group even more so. If you send me your whatsapp number I can add you to everything.