In addition to XMPP/Jabber (like Google Talk) Kopete has support for protocols MSN Messenger, AIM, Gadu-Gadu, Novell GroupWise, ICQ, Meanwhile, SMS, Yahoo, Winpopup, IRC and Skype (using the official client), supported SSL/TLS and OTR encryption (activation of the corresponding module).
Kopete allows you to add/remove/merge a lot of different contacts (buddies) from different protocols into a single MetaContact, it is possible to simultaneously connect to multiple accounts (accountan), realizes the connection to the chat (simultaneous communication with several people), you can set the status (both automatically and manual) and more...
Installation into Linux Mint:
On the screenshots below, I have not installed Kopete in KDE. I use Cinnamon. So when you install a loaded a lot of extra KDE packages. Keep this in mind.
May the Force be with you,
sudo apt install kopete