I run incremental backups all the time in which my installation does run the postfilebackup.bat. I use eventcreate to drop a message in the event log, as he suggested.
I use an RMM to check those event logs every day, and I know I am not running a full backup every day. Only occasionally do I get alarms for systems that have been shutdown during the backup window or a laptop that was taken off-site, but not turned on. Otherwise, the events are getting created, and the monitor finds them.
This has been working well for me since I got Uroni’s reply in January. I have upgraded to 1.4.10.0 at the end of October, and it is still functioning for me.
I have no idea why it wouldn’t work for incremental backups for you.