TAB v6.1.0

• Updated to 1.21.3
• Fixed issues from previous release

This update contains 2 major changes:

• Unlimited nametag mode feature and bossbar for 1.8 (which used wither entity) got removed from the plugin as previously announced here.
• On Velocity, the plugin no longer uses bridge plugin to send scoreboard packets. Instead, a new plugin called VelocityScoreboardAPI was created, which will do this job much better with a much better performance.
• If you are using TAB-Bridge with TAB on proxy, update bridge to version 6.0.0.

• Fixed an exploit on Velocity
• Fixed error

As MC 1.21.2 is approaching, this is the final update for 4.x branch. From now on, only 5.x versions will be released, which will no longer have unlimited nametag mode and bossbar for 1.8 servers.
This was originally planned to come with MC 1.22 rather than 1.21.2, however, Mojang has decided to rework entity packets in 1.21.2 and I don't see the point in adding support for it just to remove the whole feature soon after.
In case you missed it, here is the original (now updated) announcement:

Fixed compatibility with new BungeeCord builds, causing players to get disconnected with a packet encoding error.

Updated to 1.21.1

Added 1.21 support.
Unlimited nametag mode feature has now been marked for removal for the future. Read more about it and discuss it here.

Fixed "Network Protocol Error" disconnect on 1.20.5+

Hotfix from previous release.