Do all emails clients support animated timers?
All major email clients (Gmail, G Suite, Hotmail, Yahoo, Apple Mail, Samsung Mail, Office365, Outlook for Mac, AOL etc) support animated GIFs. One exception: some versions of Outlook.
Outlook recently updated its support for animated GIFs, but this only affects Office365. Outlook 2007-2019 still don’t support animated GIFs.
These Outlook versions show, however, the first frame of the animated timer and therefore customers are still able to see the actual remaining time.
Related MS Office article: The animated graphic in my e-mail message doesn't work