We're continuing to fix issues and reduce the bugs in 1.13, consider supporting the project and helping us continue.
Known bugs 1.13 client:

• Blocks which connect do not connect properly (fences, doors, stairs etc) - Click here to follow progress on GitHub. Due to connections now being serverside we're looking for help in developing an optimal solution.

Changelog (All fixes are for 1.13):

• Custom enchants (by @creeper123123321)
• Fix other enchantments (by @creeper123123321)
• Various chunk writing optimisations (by @creeper123123321)
• Disable paper block patch on 1.12 or higher (by @Logics)
• Fix biomes being ocean (by @creeper123123321)
• Fix spawn eggs sometimes being buggy (by @creeper123123321)
• Fix various NullPointerExceptions with items (by @creeper123123321)
• Fix spawner entities being wrong (by @Matsv)
• Fix item frame hitboxes (by @Matsv)
• Fix various flower pots when string is empty (by @Matsv)
• Fix falling dust particles (by @Matsv)
• Fix team colours (introduces new option in the config for toggling), based on team prefix (based on code by @JollyajaX)

Huge thanks to all the awesome people contributing code to us (listed above), the team has spent 100s of hours on this update <3

(I'm still on holiday, and will most likely have less Wi-Fi than I've had, consider posting bugs on GitHub or use our Discord - http://viaversion.com/discord)