This KB Article explains how to change the GUI version on GEN 7 devices.
NOTE: UI6 on GEN7 firewalls was originally provided solely for debugging purposes. As of SonicOS 7.1.2, the option to revert to UI6 on GEN7 firewalls is no longer supported.
This option is available for troubleshooting purposes or to navigate the firewall menu with legacy graphics.
A firewall restart is not required.
How to change from from UI7 to UI6





To revert back to UI7, you can re-enable the toggle on the diag page: How to Revert the GUI back to UI7 on Gen7 firewalls?