Installing the KOReader flatpak on ARM

I’m trying to install the KOReader flatpak on my arm7l machine.

$ flatpak install rocks.koreader.KOReader -v
F: No installations directory in /etc/flatpak/installations.d. Skipping
F: Opening system flatpak installation at path /var/lib/flatpak
F: Opening user flatpak installation at path /home/bjesus/.local/share/flatpak
Looking for matches…
F: Fetching summary index file for remote ‘flathub’
F: Loading using curl
F: Received 10001 bytes
F: Loaded indexed summary file c61cf0b6918fb1b895c9c2278d6bfbb1a040176dad364c2015aafc06ef0b9c29 from cache for remote ‘flathub’
error: No remote refs found for ‘rocks.koreader.KOReader’

Initially I thought this was because it isn’t built for my architecture. The page lists aarch64, x86_64 as the supported ones. Then I noticed that other flatpaks with the same support work just fine, for example Sliderule.

Why does Sliderule work and KOReader doesn’t, if they’re both have the same architectures supported?

arm7 is no longer supported on flathub.

Thanks @hub ! So is the reason one app works and the other doesn’t simply that it has arm7 support, but it’s just not listed in the page?

Is there anything I can do about it? I don’t know much about flatpaks - can I “compile” my own arm7 variant based on the flatpak “recipe” somehow?

Thank you!

Why is it not supported anymore?