DownThemAll! is a download manager/accelerator built as an Addon in Mozilla Firefox. Currenty, DownThemAll! is not compatible with Firefox Quantum.
You will get the following message when visiting DownThemAll! webpage:
“This add-on is not compatible with your version of Firefox.”
One alternative for DownThemAll! is uGet. uGet is an Open Source and multi-platform download manager. It works in Linux, BSD, Android and Windows.
uGet is a stand-alone application but you can install a Firefox Addon to replace Firefox’s default download manager.
Install uGet in Ubuntu
sudo add-apt-repository ppa:plushuang-tw/uget-stable sudo apt update sudo apt install uget
Install the uget-chrome-wrapper
sudo add-apt-repository ppa:slgobinath/uget-chrome-wrapper sudo apt update sudo apt install uget-chrome-wrapper
If uget-chrome-wrapper is not installed properly, you will get this error message:
unable to connect to the uget chrome wrapper
Install uGet Integration Firefox Addon
Go to uGet Integration Firefox Addon page and click “Add to Firefox”