Your PHP MySQL library version 5.5.44 differs from your MySQL server version 10.0.20. This may cause unpredictable behavior How can I fix this "error" in phpmyadmin ? Is this a serious problem, I should care about? 


Server Version: 10.0.20-MariaDB-1~trusty-log - mariadb.org binary
distribution Apache/2.4.7 (Ubuntu)
Datenbank-Client Version: libmysql 5.5.44
PHP-Erweiterung: mysqli Dokumentation
All packages are uptodate (official ubuntu 14.04 repos)
On MariaDB I use the official repos from mariadb.org


Thanks in advance!
I just fixed the problem:

apt-get remove php5-mysql
apt-get install php5-mysqlnd


I had to reinstall phpmyadmin, the errors disappeared now.