So I'll just provide a QR-Code to the grouchat and they are in?
Yes!
Is Arcane available for both IOs and Android?
Oh okay, my bad. I forgot about iOS ๐ ArcaneChat is available only for Android, but DeltaChat is available on both. They are inter-operable, so you can tell Android users to use ArcaneChat and iOS users to use DeltaChat. Or use DeltaChat for both. ArcaneChat just adds a couple features like Markdown.
And do I need a new inbox programm or an extra email if we use emsil like chat? I use thunderbird and I feel like there would be a lot of alerts popping up?
DeltaChat creates an account on its own kind of servers automatically so you don't have to worry about that.