Problem was a complicated smarthost specification which exim4 is happy to honor bug exim-config postinst could not grok. error was:
+ RET=20 Unsupported command "${if" (full line was "${if match{${lc:$header_subject:}}{MarcAtAuslanderDotNameWorkingCheck}{mail.optonline.net}\") received from confmodule. Issue may be use of continuation but I'm not sure about that. Marc Auslander <marca...@gmail.com> writes: >after the recent security update to exim4 im seeing: > >dpkg: error processing package exim4-config (--configure): > subprocess installed post-installation script returned error exit status 20 > >what now?