Philipp, The backtrace is not 100% reliable due to lack of debugging symbols, but it seems a bug in libesmtp, which is trying to call a null function. This shouldn't happen.
As far as I recall, this is the first time I'm receiving a report of segfault due to StartTLS. So, it could be some bug related with the arm architecture. Can you build the libesmtp and esmtp sources with debug info, and test it? José Fonseca
