Hi - firstly, thanks for the new release of ee, very useful.
I just wanted to highlight a feature when using multisite with subdomains. It is probably not an issue for general use but confused me a little when testing.
It seems that if you visit a nonexistent subdomain such as xxx.mywebsite.com you are presented with the opportunity to sign up as xxx. However, if you complete the signup process and then visit xxx.mywebsite.com, you are sent back to the sign up page because it has been cached.
Once the cache has been purged or if you are logged then it is fine - and of course if you haven’t visited the subdomain prior to creation it is not an issue.