Jeff King <peff@xxxxxxxx> writes: > We could send a capabilities^{} line, which Git has supported on the > client side since eb398797cd (connect: advertized capability is not a > ref, 2016-09-09). So sending it should not break even old clients > (though we would have to check what alternate implementations like > libgit2 or dulwich do; we know JGit supports it). Ah, I forgot all about that JGit workaround. Yes, we can exploit it, and any implementation that does not understand it correctly (including git before 13e67aa3 (v0 protocol: fix sha1/sha256 confusion for capabilities^{}, 2023-04-14)) does not work with JGit when cloning an empty repository anyway, so it is not all that bad. But I tend to agree with your conclusion that it may be an update for the sake of completeness to retrofit v0/v1 on the serving side. It would not help any real-world use cases all that much. Thanks.