Policy generation error when upgrading Rudder

During upgrade of Rudder, there may be transient policy generation error (shown with a red cross instead of the green tick on the top of the Web Interface), due to different upgrade order of some Rudder components.

To fix this issue if it happens, you can:

1. run "rudder agent run -u" on the Rudder server
2. log in the Web Interface - if policy generation shows a red cross, click on "Regenerate policies", which will solve the issue