Yes I noticed same problem. I can't read or write my mails via IMAP account
with SSL/TLS. Status bar only says connecting server... Sometimes when I have
waited minutes can see content of the mails.
Everything works well with version 31.
By default Icedove 38 has as "maximum # of server connections to cache" 5 via
edit>account settings>server settings>advanced when it had 1 in Icedove 31.
When I changed the parameter back to 1 the situation is still same as told
above.
Has someone test this also in Debian 8?