The vendor has published 2 unique mention(s) for this bug: 1. Previously, while some provisioning servers were upgraded and others were not, targets booting from virtual disks in private image mode or maintenance mode might fail to connect or reconnect, and some management commands failed with communication errors. Servers now communicate reliably throughout the upgrade, so these targets connect as expected and management commands succeed. 2. There can be issues with internal communications between provisioning servers during an upgrade, when some servers have been upgraded and some have not. This is due to the transition to an improved internal communications protocol between servers. If you have targets booting from virtual disks in private image mode, or targets booting in maintenance mode, they may not connect or reconnect properly. Citrix recommends not having any of these targets streaming during the upgrade. The Configuration Wizard can display a warning about these targets when you run it the first time after upgrading. Additionally, some management commands may fail with communication errors during the upgrade. When all the servers have been upgraded, there are no longer any communication issues expected. Latest urls for this bug: 1. https://docs.citrix.com/us/en/provisioning/2607-ltsr/whats-new/fixed-issues.html 2. https://docs.citrix.com/us/en/provisioning/current-release/whats-new/known-issues.html