Hi Shahriar,
That seems to have fixed the resolution issue. Thank you very much.
The thumbnails still aren’t updating.
All caching plugins are still off. And the server doesn’t have any caching set up. Different browsers, devices and networks – still no updating.
If you click on the Test Imagick 4 thumbnail on the test page, you will see the PDF looks totally different.
**UPDATE**
I found a new forum entry where you provided this information:
You have to clear the cache from Downloads > Settings > Privacy Tab. And that delete all cached thumbs.
That appears to have fixed the issue. Thanks.