I can't change the password for the Administrator account. Modification thereof is not taken into consideration. I can't also create new user. :-(
OCS SERVER VERSION : 2.2
This is maybe 'cause you have a old version of PHP5, I has the same problem but I upgrade my version of PHP5 and I can change the admin password and create new users http://serverfault.com/questions/694385/how-to-upgrade-php-5-4-to-php-5-6-on-debian-gnu-linux-7-wheezyhttp://serverfault.com/questions/404815/how-can-i-upgrade-php-to-a-higher-version-for-debian-squeeze
PHP upgrade from "PHP 5.4.45-0+deb7u2 (cli) (built: Oct 17 2015 08:26:31)" to "PHP 5.6.19-1~dotdeb+zts+7.1 (cli) (built: Mar 4 2016 07:24:43)" and an Apache2 restart worked for me! Thank you @Krios!
# nano /etc/apt/sources.listadd: deb http://packages.dotdeb.org wheezy all deb-src http://packages.dotdeb.org wheezy all deb http://packages.dotdeb.org wheezy-php56-zts all deb-src http://packages.dotdeb.org wheezy-php56-zts all# wget https://www.dotdeb.org/dotdeb.gpg# apt-key add dotdeb.gpg# apt-get update && apt-get -y upgrade# apt-get install php5# service apache2 restart