We will be upgrading FogBugz On Demand to version 8.9.106 this Wednesday night. The upgrade window will open promptly at 0200 UTC (2200 EDT) and remain open until 0300 UTC (2300 EDT). Due to the nature of this upgrade, customers should expect a service interruption up to 30 minutes (depending on the size of the account), though most will be much shorter. This interruption may occur at any time during the window.
Update: We will also be performing emergency infrastructure maintenance on some of our Kiln On Demand. We expect no customer impact, but the work is sufficiently nerve-wracking that the engineers felt better letting me do it at night. What's wrong with them we may never know. This does not change the overall maintenance window.
You can find release notes for FogBugz On Demand 8.9.106 and other helpful information at our customer service portal: help.fogcreek.com. If you have any questions, please don't hesitate to contact us!