Yesterday, 27-May-2021, the IETF published QUIC as RFC 9000 [rfc-editor.org] (text document) supported by RFC 8999 [rfc-editor.org] (text document), RFC 9001 [rfc-editor.org] (text document), and RFC 9002 [rfc-editor.org] (text document).

This means QUIC version 1 is officially standardised, and existing QUIC deployments can now move away from using draft versions.
Note: HTTP/3, the version of HTTP that runs on QUIC, is expected to be published as an official RFC soon.

In corollary news, today, 28-May-2021, Cloudflare announced that QUIC Version 1 is live on Cloudflare [blog.cloudflare.com] and that they currently see 12% of traffic using the transport protocol.

Currrently (since mid-2016), I use HTTP/2 and, for once :) am not jumping out ahead, because:
* I use Apache HTTP Server (default and dynamic serving) and they have not addressed QUIC publicly at all so far as I know.

* I also use Apache Traffic Server (cached serving) and I’d call what’s available a beta.

* In tests the difference between HTTP2 and HTTP3 in my context is mostly negligible. Single digit percentages one way or the other.
Note: I made the switch from HTTP1.1 to HTTP2 because there was a significant ~60% improvement.