# MCPRequestHandler.protocolVersions

- **Module:** MCPRequestHandler
- **Package:** LibTmuxMCP
- **Language:** Swift
- **Kind:** property
- **Source:** https://github.com/libtmux/libtmux-swift/blob/254f8b2be7eb60cacc3ffcb3ea8e456784f582df/Sources/LibTmuxMCP/MCPProtocol.swift#L16
- **Page:** https://libtmux.org/en/swift/latest/mcp/reference/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.