Set a deliberate Java client policy with ViaVersion version blocks
Accepting a protocol does not mean you want to support it. A community may choose a smaller client range because its resource pack, combat rules or accessibility testing covers only those clients. ViaVersion provides readable version blocks without changing the server world.
Record the starting point
Write down the native server version, the oldest and newest clients you intend to allow, and the installed ViaVersion build. Keep the current configuration and prepare one allowed client plus one intentionally excluded client. Use a quiet test window rather than excluding everyone during an event.
Work through the change
- Open the active ViaVersion configuration and locate its generated block-versions and block-protocols options. Read the comments supplied by the installed release before changing either list.
- Add only the intended readable version restriction to block-versions. Existing numeric blocks also apply, so inspect both lists when a client appears to be excluded unexpectedly.
- Set a concise blocked-client message using the documented message option. Tell players which client range to use; do not claim they have been banned from the community.
- Restart normally and test the two prepared clients through the public connection route. On a proxy network, repeat the check for each backend whose supported range differs.
Check the result
The allowed client should join and perform normal movement and inventory actions. The excluded client should receive the intended explanation before entering gameplay. Record the effective range alongside the release numbers so a future upgrade can repeat the same acceptance test.
If the result differs
An allowed client failing too may indicate overlapping numeric blocks, a restriction on another network component or a missing translation dependency. Compare the rejection text and startup log. Do not loosen every restriction simply because one version was entered incorrectly.
Restore the saved restriction lists and restart if the policy prevents the intended population from joining. Keep a copy of the failed rule for review. Changing an admission rule does not require changing player files or regenerating a world.