We are now able to support 1.17 throughout the network with the use of ViaVersions.
For the time being we are still recommending that where practical users still connect on 1.16.5 for the best possible experience, however do appreciate that might not always be practical / desirable.
The development team are working hard to bring support for 1.17, though it is a significant amount of work even compared to previous updates, and a lot of stuff is breaking due to Mojang's decision to bump up the minimum Java version to play their game to a non-standard / LTS release.
We hope in the coming weeks to move fully on to 1.17, but for now this should at least bridge the gap and allow everyone who has been playing / may want to join us to be able to play on the network.
Thanks everyone.