Getting mosh work on Windows with truecolor (24bit)

Question

I'm trying to get mosh.org work on Windows with truecolor (24-bit) support. Mosh includes truecolor support since version 1.4. However:

• There is no native Windows client. The website https://mosh.org/#getting points to using a Chrome extension.
• The extension is no longer supported and doesn't work with recent Chrome versions.
• Instead it's suggested to use the Ssh Extension which now includes Mosh. But only version 1.3.2.

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Then I tried to compile Mosh 1.4 from source on WSL. It compiled just fine:

% mosh --version
mosh 1.4.0 [build mosh-1.4.0-19-g1105d48]

I have COLORTERM=truecolor set. Truecolor support works locally within Windows Terminal, tested with https://github.com/termstandard/colors.

I also have

% cat ~/.ssh/config
SendEnv             COLORTERM

so that the variable propagates to the remote system.

When connecting via ssh, truecolor support works. But when connecting via mosh 1.4 (and also 1.3.2), truecolor still doesn't work.

Any ideas how to debug the problem further?

Answer 1

Turns out the solution is simple: The server-side mosh binary must also be of version 1.4+. With that fixed it works as expected!