How can I install Seamonkey on Ubuntu 18.04 LTS?
I can recommend to install SeaMonkey browser using UbuntuZilla APT repository. This package will be updated on every apt upgrade.
You need to execute the following commands to add repository, its key and package installation:
cat <<EOF | sudo tee /etc/apt/sources.list.d/mozilla.list
deb http://downloads.sourceforge.net/project/ubuntuzilla/mozilla/apt all main
EOF
sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com 2667CA5C
sudo apt-get update
sudo apt-get install seamonkey-mozilla-build
You will get SeaMonkey 2.53.2 with this method.