Quoting Pirate Praveen <praveen at onenetbeyond.org>:
> Package: dino-im
> Version: 0.1.0-5~bpo10+1
^
Note, that 0.1.0-5~bpo10+2 is in buster-backports since
2020-07-06 (one week) with tilde in Breaks and Replaces.
Where do you get the ancient backports from? ;-)