https://bz.apache.org/SpamAssassin/show_bug.cgi?id=8311
--- Comment #9 from Kent Oyer <k...@mxguardian.net> --- Based on preliminary research the Thread-Index header consists of base64 encoded binary data, where the first 8 bytes represent a timestamp, the next 14 bytes represent some kind of unique id, and then 5 bytes are added for every reply. If there are no replies, the minimum data length is 22 (8+14) bytes. 22 bytes of binary data requires 32 base64 characters. Therefore, I think the best we can do is make sure the Thread-Index header is valid base64, starts with an 'A' and is at least 32 characters long. I don't think there is an upper bound on the length since it depends on the number of replies. At some future point the first letter will become 'B' because the timestamp increases monotonically but I haven't figured out when that will happen yet. -- You are receiving this mail because: You are the assignee for the bug.
