How to convince dpkg that libssl1.0.2 is >= libssl1.0.0?

Question

I am trying to install a 3rd party .deb package that I have installed before on Debian 8. But I cannot install on a fresh Debian 9 setup because I get the following error:

dpkg: dependency problems prevent configuration of parity:
 parity depends on libssl1.0.0 (>= 1.0.0); however:
  Package libssl1.0.0 is not installed.

I do have libssl1.0.2 installed. But it is not being recognized as ">= libssl1.0.0" so I wonder how to fix this.

1. Do I install libssl1.0.0 manually? If so, how?

2. Do I symlink something? If so, what?

3. Something else?

Answer 1

libssl1.0.2 and libssl1.0.0 are different packages, providing incompatible libraries; that’s why you can’t satisfy a libssl1.0.0 dependency using libssl1.0.2.

To satisfy your package’s requirements, I’d suggest adding the Debian 8 repositories to your configuration, since Debian 8 is still supported (so if necessary you’ll get security updates). To do so, edit your /etc/apt/sources.list file, and copy every stretch line, replacing stretch with jessie (so you end up with both stretch and jessie lines). Then run apt update, and apt install libssl1.0.0 should work.

Alternatively, you can download the package (look for your architecture at the bottom of the page), and install it with dpkg -i.

In both cases, apt-mark auto libssl1.0.0 will help: that way the package will be considered for auto-removal, should it become unnecessary in the future.