If you've updated the MariaDB.repo to match the 10.11 release, it should work with the same commands.
You still need to apply the changes in my.cnf. Otherwise, MariaDB won't start.
The bind-address should look like this:bind-address = 127.0.0.1
Hello Martin,
I hope you're doing well.
Finally I was able to install MariaDB version 10.11.6 and I send you the screenshot after installation.
I thank you very much for your help and for your support, you are better and I wish great success to your work and your projects.