Sylpheed

I compiled and install version 3.4.2 a couple of days ago, and since have segmentation faults when downloading messages.
Some observations:

- The segfault is not always at the same point (i.e. not the same message number) even though nothing changed at the mail server (The number of messages outstanding did not change).

- The messages are not registered locally: Each 'Get' (re)starts downloading at the first message.

- There were some changes at my ISP. It seems they blocked port 25 recently. I had to change to port 587 for sending (SMTP), but reception was not changed.

- The segfault occurs irregularly. With 60-odd messages on the server, the crash happens near message 32, but not always the same. Sometimes it actually finishes (not very often).

I've tried to check the protocol with Wireshark, but see no errors.

My system is Slackware64-current Linux. I'm not sure how to make a debug compile to follow execution, but I did attach a backtrace.

Can I provide anything else?