Mike and I upgraded the DPM yesterday to 1.6.10. There are no schema changes in 1.6.7->1.6.10, so the upgrade involves 'downtime' of about 20s. We didn't put this into the CIC portal, but I suppose in retrospect we should have declared an 'at risk' period.
We're still running the i386 version of DPM (on top of x86_64). At some point it would be desirable to upgrade to x86_64; however, as i386 works just fine and this will involve real downtime, there is no urgent pressure to do so.
Greig has noted that dpm-updatespace in 1.6.10 has a bug in it: https://gus.fzk.de/pages/ticket_details.php?ticket=38330.