Did you update a frontend plugin but there's no visible change?
Did the change happen on your computer, but not on your phone?
In 11 cases out of 10 your browser is caching the old version (really 11, because sometimes it works, but then the cached version returns next time 🤷).
Here's how to clear the cache on most common browsers:
Google Chrome (and most Chromium-based browsers): #1288508168007061526 message
Safari: #1288508168007061526 message
Microsoft Edge: #1288508168007061526 message
Firefox: #1288508168007061526 message
Home Assistant Companion App: #1288508168007061526 message
Fully Kiosk Browser: #1288508168007061526 message
-# Thanks @ionic swan for researching those methods