It's a simple fact.
In every single thread with non US-ASCII data in subject encoded by
RFC2047 (sorry I wrote 2049 by error in my last mail) I've seen, the
subject turned to garbage after 5 or 6 messages.
The reason for that is that all implementations of RFC2047 around are
full of implementation errors.
The reason for that is that the RFC2047 encoding is full of specific
cases, hard to understand rules, and enables an amazing number of
different possibilities for the encoding of the same string.
I don't dispute the observation. However, I do dispute the reason.
In my experience the problem with RFC 2047 implementations is usually
that implementations try to "decode" RFC 2047 for the purpose of
internal representation and then to "encode" again for retransmission,
rather than to "decode" RFC 2047 only for the purpose of display.
It's the multiple encoding/decoding steps that cause problems,
especially when there's often no clear separation between text that
was originally encoded and text that was originally unencoded
in the same header field.
Keith