Hi, Using git format-patch --thread + send-mail leads to In-Reply-To/References headers added twice (with the very same value). This is not allowed according to RFC 5322 Section 3.6: https://tools.ietf.org/html/rfc5322#section-3.6 Ideally probably git-format-patch should be smart about whether In-Reply-To/References are already present... I noticed this after looking through emails catched by my spam filter more carefully. It seems that this particular violation is penalized quite harshly, leading to those emails landing in my spam folder. It seems that there are multiple kernel developers which use the above work flow and hence send emails not adhering to spec... -- Stefan
