With help from @rojinroy@poddery.com we can now install #diaspora on a Debian 11 #bullseye system using native #debian packages using my personal repo as documented in https://wiki.debian.org/Diaspora#Bullseye_Backports.2Fpersonal_repo
Once bullseye is released by end of this month (hopefully), we will be able to upload it to official bullseye-backports.