# error.Error.UnsupportedCapability

- **Module:** error.Error
- **Package:** libtmux
- **Language:** Rust
- **Kind:** constant
- **Source:** https://github.com/libtmux/libtmux-rs/blob/f0e37052c232636b61d095817046e6bfc8f2ca40/crates/libtmux/src/error.rs#L627
- **Page:** https://libtmux.org/en/rs/latest/reference/error-error-unsupportedcapability/

The running tmux is too old for a capability the caller asked for.

Distinct from [`Error::UnsupportedTmuxVersion`], which is about the
crate's own floor: this one says the crate works here and the *feature*
does not. tmux itself would usually accept the flag and quietly ignore
it, which turns "your tmux is too old" into "the command did nothing",
so it is reported rather than passed through.