How to obtain a 'version number' of an attributes

I've got a little challenge...

there is an attribute in AD call msDS-KeyVersionNumber. In AD this operational attribute increments each time the unicodePwd attribute is updated. It is typically a small integer, being the number of times that the password has ever been changed.

In Samba4, we maintain this by looking into our replication metadata (replPropertyMetaData), and returning a counter that is maintained there.

I could maintain this manually from Samba's side (this is what we did in the past), but I wanted to first check if there was something already stored that I could convert.

Thanks,

Andrew Bartlett