It’d be nice to get HTTP/2 re-enabled on the ACME API.
I think it was disabled because of boogs in an older version of Go. The relevant bugs, I believe, have been fixed in Go 1.6.2. They were around the handling of hop-by-hop headers like Connection, iirc.
I have some large certificates and keeping a nice, long-lived, multiplexed connection open would be a handy speed and reliability boost.