After an upgrade to Madrid, the ServiceNow logo does not appear to be refreshed:
The image has been refreshed but may not update in the browser cache.
For Chrome browsers, this can be cleared by following the below procedure:
1. Navigate to chrome://settings/clearBrowserData
2. Leave "Cached images and files" ticked, and change the Time range to "All time"
3. Refresh the instance page again, the new icon should now load correctly.