Pidgin is installable for ARM64 on the Cosmo but to make it useful you need to add a couple of Plugin's.
Assuming you have installed Pidgin lets first setup Slack:
sudo apt install git ;Install git if it is not installed
sudo apt install make ;Installs make if not installed
sudo apt install libpurple-dev ;required lib for the plugin
next clone the open source plug-in locally
git clone
https://github.com/dylex/slack-libpurple.gitcd slack-libpurple
sudo make install
Now lets do the same for the Skype plugin
First lets ensure the pre-req. libs are installed
sudo apt-get install libjson-glib-dev
sudo apt-get install cmake gcc
now lets clone the repo
git clone
https://github.com/EionRobb/skype4pidgin.gitand then
cd skype4pidgin/skypeweb
make
sudo make install
Now Skype is also completed.
If Pidgin was running when you did these installs you will need to close it and relaunch to see the plugins.