In the link above I could not find the java example (404; did not search any further), but http://flylib.com/books/en/2.55.1.80/1/ show under "10.5.3.1 Extensions" a perl example for the LDAP extension mentioned. Maybe that helps

I did express an interest on the mailing list some months back in writing a patch to implement this. I asked if anyone could point me in the right direction to start. I'm proficient in C, C++, Java and even vaguely x86 assembly, so hopefully I could cope with a little Objective C if assisted in starting!

The password modify exop is already used when you have "passwordPolicy yes".
But the ppolicy support had it's own bugs, see bug 0001719.

Perhaps a new conf option should be added to be able to use the password modify exop without ppolicy.

Which version was the EXOP first added in? I tested a few versions back and found SOGo directly modifying the userPassword attribute even with password policy enabled.

I will attempt a re-test ASAP but sadly only have a production environment in which to do it at the moment, so it may take a few days...

The password modify exop is already used when you have "passwordPolicy yes".
But the ppolicy support had it's own bugs, see bug 0001719.

Are you talking about the ppolicy overlay in OpenLDAP? This is not a requirement for LDAP Password Modify Extended Operation. Could you give an option to simply activate the use of EXOP without depending on ppolicy?

Yes, it is the reverse : LDAP Password Modify Extended Operation use is a prerequisite for the ppolicy overlay.
A new conf option o simply activate the use of the EXOP would be a good thing.