Ubuntu 20.04 dropped qt4 and all libqt4-* dependencies in its official repos. My knowledge about version conflict and install-breaking actions is limited, so before any unthoughtful action is taken, I would want the community's take about this.

Would it be possible to get qt4 to install on Ubuntu 20.04, and if so, which source would not end up breaking the install?

Alternatively, what container method would be the lightest for apps relying on qt4? My usecase for qt4 is solely for some Xilinx ISE components, nothing else, so the lightweight criteria is really important.


3 Answers 3


Adding this PPA repository to your system may solve.

sudo add-apt-repository ppa:rock-core/qt4
sudo apt-get update

Then run to install qt4.

sudo apt-get install libqtcore4

Download required packages from https://packages.ubuntu.com/bionic/ or http://archive.ubuntu.com for the Ubuntu 18.04 LTS but on Ubuntu 20.04 LTS. Then install using sudo apt-get install -f ./<package>.deb


While recommended against you can download an old version of the package and force its installation. This could potentially break your installation, so be prepared to fix package conflicts. From that link:

The reason things can break is because the software packaged for one Debian release is built to be compatible with the rest of the software for that release. For example, installing packages from bullseye on a buster system could also install newer versions of core libraries including libc6. This results in a system that is not testing or stable but a broken mix of the two.

If you still need to install an older package, you can follow the instructions jitendra gave in their answer:

  • On the newer Ubuntu release, download the required packages from https://packages.ubuntu.com/bionic/ or http://archive.ubuntu.com but for an older release (like 18.04).
  • In the download folder, install the packages using the force flag (-f) like sudo apt-get install -f ./<package>.deb Notice that ./ precedes the downloaded file; this tells apt that you're installing a local package rather than from the official repositories.

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