I'm attempting to upgrade my Dovecot installation to 2.3.2.1. My SSL certificate authority provides a bundle containing their CA, plus intermediate CAs, which I configure using the 'ssl_ca' option. The comments in the configuration file say to only set this when you're requiring client certificates, which I'm not, but fetchmail complains with a "Server certificate verification error, Broken certificate chain" error if that setting is not set. This works fine with Dovecot 2.2.34.
After upgrading to 2.3.2.1, fetchmail throws that error whether 'ssl_ca' is set or not. Dovecot 2.3.2.1 reports the error
SSL routines:ssl3_read_bytes:tlsv1 alert unknown ca: SSL alert number 48
in the logs when attempting the TLS handshake. The permissions on the CA bundle haven't changed and should still be readable by Dovecot.
I'm running Gentoo Linux on x86_64 and mail is stored on an ext4 file system. I'm attaching my config files for both Dovecot 2.2.34 and Dovecot 2.3.2.1.