To make sure my PC wont 'upgrade' unison and unison-gtk I created a file with filename 'unison' in the folder /etc/apt/preferences.
On both, Laptop and PC, i did remove in the hidden folder '.unison' (in my home directory) all files, with a filename starting with 'fp.', that are created after I had updated laptop A to a newer version of ubuntu.
So what saved me was downloading those both deb-Files, I have allready installed on my Laptop. The System and Arch are optional added filters, for example System could be redhat, redhat-7.2, mandrake or gnome, Arch could be i386 or src, etc. It is part of the CentOS extras repository and can be installed by running the following command: sudo yum install centos-release-scl Installing Python 3 on CentOS 7 Now that you have access to the SCL repository, you can install any Python 3.x version you need. And same has to be done for unsion-gtk. CentOS 7 ships with Python 2.7.5 which is a critical part of the CentOS base system. This has to be done bypassing apt/synaptics, using dpkg. In fact I decided to install the deb-File I have on my Laptop also on the PC, where I have a different distro. Similar problem - I could resolve it by installing identical deb file for unsion on both PC - and deleting some files.
