Whenever I send a mail with really long subject, Squirrelmail fails at the Subject header folding, and inserts extra spaces.
Example: I send the mail with subject: "this is a really really very long subject line to make a good example of what my problem is"
What squirrelmail sends out is this: (I replaced the spaces with underscore at the line break so that it is more visible, that there are a plenty of extra spaces added.)
Subject: this is a really really very long subject line to make a good_
_____example of what my problem is
According to RFC 2822, folding and unfolding should add and remove only the CRLF, and not the whitespaces.
I have the problem with 1.4.9a and 1.4.10a. (It's a production environment, I can't test other versions, unfortunately.) Others on the SQ mailing list confirmed the same error in version 1.4.13.
The extra spaces are NOT visible in SquirrelMail itself, just in other mail readers (Thunderbird e.g.), or in the message source itself.