I'm running a server with just my mod which bundles cardinal-components-entity and am unable to join unless I also install the mod in the client due to error Client disconnected with reason: This server requires Cardinal Components API (unhandled packet: cardinal-components:entity_sync). This is a new regression introduced in 1.20.5+ / v6.

Apologies, works now.

Hello, this is addressed in the migration guide : https://ladysnake.org/wiki/cardinal-components-api/upgrade-instructions/CCA-6-changes#client-optional-components

Could you try again with the relevant override on your component ? (Assuming your mod does use AutoSyncedComponent somewhere)

Might be related to / duplicate of #173? Sounds similar but I'm not using scoreboards just entities