You can either install Gajim on your system or use the portable version. Gajim Portable allows you to take everything with you in just a single folder.
If you are curious, you can also try the latest nightly of Gajim. But be advised, nightlies can be unstable. Make sure to have a backup of your profile folder. Migrating back is not possible without complications.
MacOS instructions to follow.
Install instructions (Linux)
Ubuntu and Debian
sudo apt install gajim
To install Gajim’s OMEMO plugin for example:
sudo apt install gajim-omemo
Available in Fedora packages.
sudo dnf install gajim
Available in openSUSE packages.
sudo zypper install gajim
To install Gajim’s OMEMO plugin:
sudo zypper install gajim-plugin-omemo
Available in Arch Linux packages.
sudo pacman -S gajim
Gajim plugins are available via AUR.
Available in FreeBSD via FreeBSD ports.
cd /usr/ports/net/gajim/ && make install clean
Available in Gentoo packages.
sudo emerge gajim
Nightly package from git (Debian, Ubuntu)
In order to install the nightly package from git, you need to use the unstable repository (or at least backports).
sudo apt remove gajim
Add the GPG key:
wget -q https://gajim.org/gajim.key -O - | sudo apt-key add -
Add the repository:
sudo sh -c "echo deb https://ftp.gajim.org/debian unstable main > /etc/apt/sources.list.d/gajim.list"
Update the repository:
sudo apt update
Install Gajim (stable branch nightly):
sudo apt install gajim-nightly
Or install Gajim (current development nightly):
sudo apt install gajim-default-nightly
If you want to dig through Gajim’s history or you just liked the older version better, have a look at the old releases.