I really wish WP had a core method for major plugin updates like this that were likely going to break things. It's come up before (ACF).

I've only been testing the new CF plugin on a few "non-critical" sites (like my blog, and a few low traffic cliets). I've had mostly failures (no controls on settings page, or if the controls show they don't work).

I love the design and that we can _finally_ (in theory) purge that cache from the WP dashboard, that's a huge win. The plugin should have had a more extensive beta test through because it's clearly a problem for a lot of users, most not savvy enough to troubleshoot/rollback on their own.

My biggest concerns are that:
#1 it's been stated it doens't support multisite. I'm not sure what that really means though since I've got it working on 2 small multisite installs... maybe they just mean there is no global configuration for multisite, it's configured sub-site by sub-site... it's not clear, but it sure _should_ support multiste.
#2 I have over 15 CloudFlare accounts (mine, plus clients). Not sites, heck I have 15 sites in my own CloudFlare account, and some clients have just as many. Per the support threads it seems like the plugin actually cares which CloudFlare account your logged into, which is crazy, what's the point of the API Key. Maybe... it just cares what account your logged into when you install? or when you upgrade? again, that's not really clear.

Thankfully, while the settings page still doesn't work across a dozen sites I've tested on, the sites all load and perform just fine. I haven't seen any 5xx errors or site down conditions (I thankfully missed the HTTP2 push header bug)