We’re aware of a few issues, and are monitoring other reports closely.
You can find more details in this article here:
https://support.zwift.com/en_us/zwiftpower-known-issues-rJQTEJzqP
If you’re seeing something that’s not covered in that article, please find the relevant forum post (if it exists) and add to it with your comments, findings, and an upvote.
We love this site as much as you, and we understand how integral it’s become to racing on Zwift. We’re doing our best to get everything ironed out, and it’s like Shuji said: migrating legacy software to a non-legacy server can be complicated business.
Thanks for all your help so far. You’re all truly what make Zwift great!