I've applied the emergency 3.8.8 firmware upgrade to my 2860 and now find the DMZ feature is completely broken.

Before I wipe and spend hours reconfiguring the device, has anybody else seen this problem?

No DMZ setup here, but did notice on my 2860n that it seemed to require 2 attempts to update to 3.8.8 from 3.8.7 - i.e. the first update showed no errors, but stayed at 3.8.7 until I ran the update a second time.

Yes, I think I'm seeing an issue too.
DMZ hosts didn't appear to work, although if I joined the external IP to the Nat pool that seemed to fix it.
Something is not quite right - I'll have another look at what firmware it says it's running later, too.

Incoming connections are correctly forwarded, but outgoing connections are all NAT'ed via the main public IP address of the router. To get around it, I've added rules in the source routing/load balancing menu but it's not ideal and I suspect costly on the router's CPU.

This issue was fixed a couple of firmware revisions ago and reappeared with the last quick update. The device now also has most of the features of the 2862 which is quite nice, but probably unintentional.

Steve

3.8.9 has been released (main site, not UK yet) so may be worth trying this.