# MCPRequestHandler.protocolVersions

- **Module:** MCPRequestHandler
- **Package:** libtmux-swift
- **Language:** Swift
- **Kind:** property
- **Source:** https://github.com/libtmux/libtmux-swift/blob/f02a4668570e1cc5198c941413750e021f42c214/Sources/LibTmuxMCP/MCPProtocol.swift#L15
- **Page:** https://libtmux.org/reference/swift/mcprequesthandler-protocolversions/

The revisions this server speaks, newest first.

A client's requested revision is echoed back when it is one of these, so
a new client is not held to an old shape and an old one is not handed a
new one. Anything unrecognised gets the newest, which is what the
specification says to do.