Flatpak in raspeberry os

I'm trying to install Flatpak and I'm having issues; I'm getting the following error: Err:1 mirrordirector.raspbian.org/raspbian stretch/main armhf bubblewrap armhf 0.1.7-1 404 Not Found [IP: 2a00:1098:0:80:1000:75:0:3 80] Err:2 mirrordirector.raspbian.org/raspbian stretch/main armhf libostree-1-1 armhf 2016.15-5 404 Not Found [IP: 2a00:1098:0:80:1000:75:0:3 80] Err:3 mirrordirector.raspbian.org/raspbian stretch/main armhf flatpak armhf 0.8.9-0+deb9u1 404 Not Found [IP: 2a00:1098:0:80:1000:75:0:3 80] Err:4 mirrordirector.raspbian.org/raspbian stretch/main armhf xdg-desktop-portal armhf 0.5-1 404 Not Found [IP: 2a00:1098:0:80:1000:75:0:3 80] Err:5 mirrordirector.raspbian.org/raspbian stretch/main armhf xdg-desktop-portal-gtk armhf 0.5-1 404 Not Found [IP: 2a00:1098:0:80:1000:75:0:3 80] E: Failed to fetch mirrordirector.raspbian.org/raspbian/pool/main/b/bubblewrap/bubblewrap_0.1.7-1_armhf.deb 404 Not Found [IP: 2a00:1098:0:80:1000:75:0:3 80] E: Failed to fetch mirrordirector.raspbian.org/raspbian/pool/main/o/ostree/libostree-1-1_2016.15-5_armhf.deb 404 Not Found [IP: 2a00:1098:0:80:1000:75:0:3 80] E: Failed to fetch mirrordirector.raspbian.org/raspbian/pool/main/f/flatpak/flatpak_0.8.9-0+deb9u1_armhf.deb 404 Not Found [IP: 2a00:1098:0:80:1000:75:0:3 80] E: Failed to fetch mirrordirector.raspbian.org/raspbian/pool/main/x/xdg-desktop-portal/xdg-desktop-portal_0.5-1_armhf.deb 404 Not Found [IP: 2a00:1098:0:80:1000:75:0:3 80] E: Failed to fetch mirrordirector.raspbian.org/raspbian/pool/main/x/xdg-desktop-portal-gtk/xdg-desktop-portal-gtk_0.5-1_armhf.deb 404 Not Found [IP: 2a00:1098:0:80:1000:75:0:3 80]

those addresses don't exist. eg, http://mirrordirector.raspbian.org/raspbian stretch does not exist. It is now http://mirrordirector.raspbian.org/raspbian/dists/stretch/ but that is empty, cause stretch is old. basically, whatever flatpack is, the person that made it needs to update. Or you're using an old install script for it and need to find the updated one.