Support for Minecraft 1.19.1 has been added to the network as it's been officially released. You are free to update to 1.19.1 or remain on 1.19 for now. Should you join using the newest version on Java Edition, you will see this notification on the corner of your screen:

This is normal and caused by us still running 1.19 internally; there's nothing to be worried about. The plan is to test how our custom chat system interacts with the new verified messages introduced by Mojang in the next few days. Once everything is looking good, we will properly update and the notification should go away.