ViaBackwards

On Fabric, use either ViaFabric or ViaFabricPlus. To override the included version

in ViaFabric, put ViaBackwards into the mods folder
in ViaFabricPlus, put ViaBackwards into the ViaFabricPlus/jars folder

Depending on the platform and version, this also requires ViaVersion.

Requires Java 17. See here how to update your installed Java version. As a last resort, you can download Java 8 downgraded builds from our ci.

Get access to Via* with new MC version support early

Starting with 1.20.5, ViaVersion and ViaBackwards will only be released a day or so after a Minecraft update unless the protocol changes of the update were trivial. If you want early-access, usually days or even weeks before the final release, you can subscribe to either:

GitHub Sponsors (preferred option, also comes with source code access. Use the /verify command on this Discord after), or alternatively
Patreon (see the highest tier and make sure to link Patreon to your Discord account under Discord Settings->Connections)

Note on release channels

It is recommended to always use the latest beta release. Alpha builds are used for work on snapshot version compatibility or other cutting-edge changes.

Always use the same build channel across the ViaVersion, ViaBackwards, and ViaRewind projects.

Releases/Dev Builds

You can find releases in the following places:

Hangar (for our plugins): https://hangar.papermc.io/ViaVersion/ViaBackwards
Modrinth (for our mods): https://modrinth.com/mod/viabackwards
GitHub: https://github.com/ViaVersion/ViaBackwards/releases

Dev builds for all of our projects are on our Jenkins server:

Jenkins: https://ci.viaversion.com/view/ViaBackwards/

Known issues

1.17+ min_y and height world values that are not 0/256 are not supported. Clients older than 1.17 will not be able to see or interact with blocks below y=0 and above y=255
<1.17 clients on 1.17+ servers might experience inventory desyncs on certain inventory click actions
Sound mappings are incomplete (see here)

Special Thanks

YourKit supports open source projects with innovative and intelligent tools for monitoring and profiling Java and .NET applications. YourKit is the creator of YourKit Java Profiler, YourKit .NET Profiler, and YourKit YouMonitor.