Upgrading from 4.2 to 4.3 or 4.3.1 does not require any changes to your configuration and scripts. The only notable change in these versions is the following:
The asynchronous syslog implementation was reported to malfunction
on some systems (notably on Solaris), so this release does not enable
it by default. The previous meaning of the --enable-syslog-async
configuration option is also restored. Use this option in order to
enable asynchronous syslog feature. To set default syslog
implementation, use DEFAULT_SYSLOG_ASYNC
configuration variable
(see syslog-async).
The following deprecated features are removed:
#pragma option ehlo
statement.
It became deprecated in version 4.0. See pragma-option-ehlo.
#pragma option mailfrom
statement.
It became deprecated in version 4.0. See pragma-option-ehlo.
It became deprecated in version 3.1. See 30x-31x.
They are deprecated since version 4.0. See 31x-400.