Having the same problem with libssl1.0.0 library, ubuntu has dropped package since 18.04 missing library reference

$ sudo dpkg -i lmc_1.2.37_x86_64_min.deb       
Seleccionando el paquete lmc previamente no seleccionado.
(Leyendo la base de datos ... 367375 ficheros o directorios instalados actualmente.)
Preparando para desempaquetar lmc_1.2.37_x86_64_min.deb ...
Desempaquetando lmc (1.2.37) ...
dpkg: problemas de dependencias impiden la configuración de lmc:
 lmc depende de libssl1.0.0; sin embargo:
  El paquete `libssl1.0.0:amd64' no está instalado.

dpkg: error al procesar el paquete lmc (--install):
 problemas de dependencias - se deja sin configurar
Procesando disparadores para bamfdaemon (0.5.3+18.04.20180207.2-0ubuntu2) ...
Rebuilding /usr/share/applications/bamf-2.index...
Procesando disparadores para gnome-menus (3.36.0-1ubuntu1) ...
Procesando disparadores para desktop-file-utils (0.24-1ubuntu3) ...
Procesando disparadores para mime-support (3.64ubuntu1) ...
Procesando disparadores para hicolor-icon-theme (0.17-2) ...
Se encontraron errores al procesar:
 lmc

$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 20.04.1 LTS
Release:	20.04
Codename:	focal

Dependency problem on pop os as well :/

$ uname -a
Linux pop-helpdesk 5.8.0-7630-generic #32~1609174078~20.10~4b8d17c-Ubuntu SMP Tue Dec 29 20:41:42 UTC x86_64 x86_64 x86_64 GNU/Linux

$ sudo dpkg -i lmc_1.2.37_x86_64_min.deb
Selecting previously unselected package lmc. (Reading database ... 220000 files and directories currently installed.) Preparing to unpack lmc_1.2.37_x86_64_min.deb ... Unpacking lmc (1.2.37) ... dpkg: dependency problems prevent configuration of lmc: lmc depends on libaudio2; however: Package libaudio2 is not installed. lmc depends on libqt5xml5; however: Package libqt5xml5 is not installed. lmc depends on libqt5webkit5; however: Package libqt5webkit5 is not installed. lmc depends on libssl1.0.0; however: Package libssl1.0.0 is not installed.

dpkg: error processing package lmc (--install): dependency problems - leaving unconfigured Processing triggers for gnome-menus (3.36.0-1ubuntu1) ... Processing triggers for desktop-file-utils (0.24-1ubuntu4) ... Processing triggers for mime-support (3.64ubuntu1) ... Processing triggers for hicolor-icon-theme (0.17-2) ... Errors were encountered while processing: lmc

Looks like only libssl1.1 is available, could it be possible to make it depend on 1.1 instead?

$ sudo apt search libssl1
Sorting... Done Full Text Search... Done libssl1.1/groovy-security,groovy-updates,now 1.1.1f-1ubuntu4.1 amd64 [installed] Secure Sockets Layer toolkit - shared libraries

### After a lot of digging i found a solution that works on ubuntu 20.04 and dists built on the same version like pop os.

Add this repo: deb http://security.ubuntu.com/ubuntu bionic-security main

echo 'deb http://security.ubuntu.com/ubuntu bionic-security main' | sudo tee -a /etc/apt/sources.list

Add the key for the repo
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3B4FE6ACC0B21F32

Then update and cache policy
sudo apt update && apt-cache policy libssl1.0-dev

With a little luck now you should be able to instal libssl1.0
sudo apt-get install libssl1.0-dev

If every thing when fine you can now install lmc_1.2.37_x86_64_min.deb with your package manager or
sudo dpkg -i lmc_1.2.37_x86_64_min.deb

Dependency problem on pop os as well :/

$ uname -a Linux pop-helpdesk 5.8.0-7630-generic #32~1609174078~20.10~4b8d17c-Ubuntu SMP Tue Dec 29 20:41:42 UTC x86_64 x86_64 x86_64 GNU/Linux

$ sudo dpkg -i lmc_1.2.37_x86_64_min.deb Selecting previously unselected package lmc. (Reading database ... 220000 files and directories currently installed.) Preparing to unpack lmc_1.2.37_x86_64_min.deb ... Unpacking lmc (1.2.37) ... dpkg: dependency problems prevent configuration of lmc: lmc depends on libaudio2; however: Package libaudio2 is not installed. lmc depends on libqt5xml5; however: Package libqt5xml5 is not installed. lmc depends on libqt5webkit5; however: Package libqt5webkit5 is not installed. lmc depends on libssl1.0.0; however: Package libssl1.0.0 is not installed.

dpkg: error processing package lmc (--install): dependency problems - leaving unconfigured Processing triggers for gnome-menus (3.36.0-1ubuntu1) ... Processing triggers for desktop-file-utils (0.24-1ubuntu4) ... Processing triggers for mime-support (3.64ubuntu1) ... Processing triggers for hicolor-icon-theme (0.17-2) ... Errors were encountered while processing: lmc

Looks like only libssl1.1 is available, could it be possible to make it depend on 1.1 instead?

$ sudo apt search libssl1 Sorting... Done Full Text Search... Done libssl1.1/groovy-security,groovy-updates,now 1.1.1f-1ubuntu4.1 amd64 [installed] Secure Sockets Layer toolkit - shared libraries

### After a lot of digging i found a solution that works on ubuntu 20.04 and dists built on the same version like pop os.

Add this repo: deb http://security.ubuntu.com/ubuntu bionic-security main

echo 'deb http://security.ubuntu.com/ubuntu bionic-security main' | sudo tee -a /etc/apt/sources.list

Add the key for the repo sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3B4FE6ACC0B21F32

Then update and cache policy sudo apt update && apt-cache policy libssl1.0-dev

With a little luck now you should be able to instal libssl1.0 sudo apt-get install libssl1.0-dev

If every thing when fine you can now install lmc_1.2.37_x86_64_min.deb with your package manager or sudo dpkg -i lmc_1.2.37_x86_64_min.deb

This solution worked thanks! However completely agree that this should be upgraded to libssl1.1 -- libssl1.0 gave me a lot of warning about being deprecated.