The following discusses the threading of patches. https://u-boot.readthedocs.io/en/latest/develop/sending_patches.html#sending... I see the following mentioned there. "Make sure that your mailer adds or keeps correct In-reply-to: and References: headers, so threading of messages is working and everybody can see that the new message refers to some older posting of the same topic. Uncommented and un-threaded repostings are extremely annoying and time-consuming, as we have to try to remember if anything similar has been posted before, look up the old threads, and then manually compare if anything has been changed, or what."

Does it mean that when a newer version of a patch is sent, it should keep a pointer to the previous version's thread by using the In-reply-to field? I have hardly seen anyone doing this.