Minecraft 1.20.5 has changed syntax on many commands, so most commands will no longer work without an update.
An update is in progress, you can check compatibility progress here. Snapshot can be selected from the dropdown menu.
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Try the Commands Troubleshooting and Help page if you get stuff with server errors.
Minecraft Versions Permalinks
If you find yourself using a particular version all the time, you can link directly. There is some crossover between versions, so there will be quirks.
