Versions and clients

The short answer#

The network runs on 1.21+. Older clients get in through ViaVersion,
and the supported range is 1.7.2 – 1.21.x.

That means a client from 2013 can technically connect. It also means a client
from 2013 will feel wrong in places, because it is being translated.

What "supported through ViaVersion" actually means#

ViaVersion translates packets between your client and the server. Most things
survive that translation. Some do not:

• Blocks and items that did not exist in your version cannot be shown to you.

They usually turn into something else, or into nothing.

• Newer mechanics behave the way the server implements them, not the way your

old client draws them. Attack cooldowns are the classic example.

• Menus with a lot of custom text can render oddly.

None of that is a bug you need to report. If something looks strange and you
are on an old version, switch to a current one and try again. That single
step rules out most of what ends up in the help category.

Clients#

The vanilla launcher is fine. So are the usual performance setups — Fabric or
Forge with rendering and FPS mods, and the launchers built around them.

What is not fine is anything that plays for you or shows you what you should
not see. The rule is about effect, not about a list of names: if a mod gives
you information the game does not give everyone, or takes an action you did not
take, it is cheating.

Concretely, and non-exhaustively:

If you are unsure about one specific mod, ask in
the help category before you use it. Asking costs
nothing. The rules page has the binding wording.

Snapshots#

Snapshots and pre-releases are not supported. They change protocol numbers
between builds, and ViaVersion catches up afterwards, not in advance.