0.13.4 is a pretty old version of the installer and I guess it didn’t support the FP4 yet.
I assume the easiest would be to use the snap version that is at 0.18.1.
If you can’t or don’t want to use snap, then maybe building the installer from sources could be an idea.
Edit: out of curiosity I had a look how difficult it is to create an AppImage file of the easy-installer that is one self-contained binary that runs on any linux distribution without the need to install anything.
Turns out it was pretty easy 
I’ve uploaded the AppImage to my murena cloud account: https://murena.io/s/fn9YCWX4if9Gfzy
easy-installer.AppImage is the executable, easy-installer.AppImage.sha256sum contains a file checksum and easy-installer.AppImage.sha256sum.asc is a signature of the checksum file with my PGP key.
I hope that’s not too gibberish for everybody…