Changes in TARDIS version 6
Version 6 of the TARDIS plugin contains some major rewrites of the plugin's code to update it to reflect the way Minecraft has changed custom item models.
You may find that you need to rebuild your TARDIS exterior, and update custom TARDIS items, lights and blocks.
If you are updating from a version earlier than v5.x.x, you should update to the latest TARDIS 1.21.3 build — follow the instructions on the Updating from v4.x.x to v5.x.x page.
Items
Items can be updated by running the /tardis item hand command while holding the item in your main hand, or running /tardis item inventory to update all items in your current inventory.
Custom blocks and lights
To update the custom blocks and lights in your TARDIS, run the /tardis update blocks command. This will attempt to update blocks in the ARS grid as well, but may take some time.
Resource pack
Make sure you are using the latest version of the TARDIS Resource Pack.