Evaluate shipping Claws Mail 3.11.1+

According to Claws mail developers, ‘If you want to be fully in control and exact in your requirements’ there is a big difference between Claws mail 3.11.1 and 3.8 which is shipped with Tails. With the newer version, I could configure TLS like

gnutls_set_priority=1
gnutls_priority=NONE:+VERS-TLS1.0:+VERS-TLS1.1:+VERS-TLS1.2

See the thread at http://lists.claws-mail.org/pipermail/users/2014-November/011593.html

Claws mail 3.11.1 is on Debian testing. https://packages.debian.org/jessie/claws-mail

Apparently the improvements on the security aspects are big, though I have no idea of other problems that might arise

Related issues

Related to #8301 (closed)
Related to #9302 (closed)

Original created by @emmapeel on 8305 (Redmine)

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