# version.JSON_LAYOUTS

- **Module:** version
- **Package:** libtmux
- **Language:** Rust
- **Kind:** constant
- **Source:** https://github.com/libtmux/libtmux-rs/blob/f0e37052c232636b61d095817046e6bfc8f2ca40/crates/libtmux/src/version.rs#L790
- **Page:** https://libtmux.org/en/rs/latest/reference/version-json_layouts/

`window_layout` and `select-layout` using a JSON subset instead of the classic checksum-prefixed string, and so [`crate::LayoutSpec::Saved`] accepting one.

tmux's own `CHANGES FROM 3.7c TO 3.8` names the release: "Layout
strings now use a JSON subset format ... The old format is still
accepted; control mode clients receive old layouts unless they set the
new-layouts flag." Below this release a JSON string is refused as an
unrecognised layout, with no hint that the value is simply from a
newer tmux.