Hopefully some helpful tips for anyone getting started with the new Next Experience aka "UI 2022" in San Diego.

How to enable Next Experience

Activating Next Experience | ServiceNow Docs

1. Open sys_properties.list
2. Set property glide.ui.polaris.experience to true
3. Logout and in
4. From the "ALL" menu type incident.list and press enter.
   

How to disable Next Experience for a specfic app or page?

PolarisUI - Scoped | ServiceNow Docs

Option 1 - Disable for each page on the table "sys_page_theme"

1. Open sys_page_theme.list
2. Add a new entry for incident and incident_list
   
3. Open Incidents page. You will still have the unified header but the page list will be in UI 16 mode.
   

Option 2 - Append the parameter sysparm_use_polaris=false to the URL of any classic UI page

Exploring themes in Next Experience | ServiceNow Docs

UI pages with the $ prefix automatically append this parameter. The parameter automatically applies to pages the user goes to next.

How to disable Next Experience for a specfic user?

PolarisUI - Scoped | ServiceNow Docs

1. Open sys_user_preference table and create a new record "glide.ui.polaris.use" for the user
   
2. Impersonate User to verify
   

For more information about Next Experience system properties and user preferences, see Next Experience system properties.