It seems like the system is back up and running sending emails when upgrades do go through, and they seem to be processing the upgrades one leg at a time. I purchased a Q fare PVG-SFO-SEA-SFO-PVG on 4/23 and immediately applied GPU knowing the flights were waitlisted. On 5/3 the SFO-PVG leg cleared, then on 6/7 the SEA-SFO leg cleared. Each time it cleared an email was sent. YMMV.