You probably need to re-install it selecting the Izzy repo. The app in the offical repo is signed differently from the one on Izzys and the F-Droid app will stay on the repo your app is installed from.
Izzy repo usually updates daily while official one is always a few days behind.
Edit: you might wanna get Droid-ify to have a better F-Droid experience.
I added the izzydroid repo and I don’t know if the repo just isn’t working or what, but there is no newer version listed for me.
You probably need to re-install it selecting the Izzy repo. The app in the offical repo is signed differently from the one on Izzys and the F-Droid app will stay on the repo your app is installed from.
Izzy repo usually updates daily while official one is always a few days behind.
Edit: you might wanna get Droid-ify to have a better F-Droid experience.
I don’t know if I solved it by disabling and re-enabling the repo but that’s one of the things I tried and later I could see it.