What QUIC Versions Does LSWS Support?

Initially, LSWS supported Q035, Q037. As of this writing, the latest version of LSWS supports Q035, Q037, Q038, Q039, but this will continue to change, as both Chrome and LiteSpeed Web Server evolve. LSWS will automatically show the supported QUIC versions through the headers.

Please do not change the LSWS QUIC versions setting! Leave it as Not Set, and the alt-svc response header will automatically display the currenly-supported versions.

Sometimes you cannot see the latest supported version from the QUIC header, even if LSWS's latest release supports them. For example, at the time of this writing, LSWS supports Q035, Q037, Q038, Q039, but the page header only shows 35, 37. Why?

One possible reason is that you are using an old version of LSWS. You should always upgrade to the latest build of the latest version.

If you have upgraded to the latest version but still see the above inaccuracy, the most likely explanation is that you manually set QUIC Versions in LSWS's QUIC settings.

When QUIC Versions is not left as Not Set, the manual configuration will soon become outdated or wrong.

Why have a QUIC Versions setting at all, if you are not supposed to use it?

The idea behind exposing supported versions is to give the user the ability to disable a particular QUIC version in the case of a security vulnerability or bug. This is the only occasion during which you should set QUIC Versions manually.

Don't forget to revert the setting back to Not Set once the bug is fixed. Failure to do so will cause your configuration to become outdated in the future.