I am super impressed. Last night I switched my #deltachat relay server to one I found running in Japan. It was simple. I didn't have to re-invite any of my connections. Everything just worked. This ability is really a big deal and I'm surprised it is not being talked about more loudly. Not only is Delta Chat decentralized, but you can easily recover from a relay server shutting down without losing contacts. This is even better than Mastodon's migration feature.