controlled by the build-time option SUPPORT_PIPE_CONNECT.
PP/01 Unbreak heimdal_gssapi, broken in 4.92.
+JH/27 Bug 2404: Use the main-section configuration option "dsn_from" for
+ success-DSN messages. Previously the From: header was always the default
+ one for these; the option was ignored.
Exim version 4.92