# version.TmuxVersion.require

- **Module:** version.TmuxVersion
- **Package:** libtmux
- **Language:** Rust
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-rs/blob/8a648c0894dfffc9303583f753b6c8ae01f2fe76/crates/libtmux/src/version.rs#L464
- **Page:** https://libtmux.org/reference/rs/version-tmuxversion-require/

```
version.TmuxVersion.require(self, capability: &'static str, needs: ReleaseVersion) -> Result<(), Error>
```

Refuse a capability this release is too old for.

tmux usually accepts an unknown flag and ignores it, so without this
"your tmux is too old" arrives as "the command did nothing". A
development build carries no numbered release to compare and is taken
at its word rather than refused.

# Errors

Returns [`Error::UnsupportedCapability`] when this release is below
`needs`.