then remove; from php.ini file:
to
extension=php_mbstring.dll
If it still does not work, cancel the php setting without removing the database from your phpmyadmin. Reinstall it.
NB: * if you want to delete everything, specify everything that you need.
sudo apt-get remove php*
Then install the necessary php and modules of the PHP version. here, php 7.1:
sudo apt-get install php7.1 php7.1-cli php7.1-common libapache2-mod-php7.1 php7.1-mysql php7.1-fpm php7.1-curl php7.1-gd php7.1-bz2 php7.1-mcrypt php7.1-json php7.1-tidy php7.1-mbstring php-redis php-memcached
restart apache and check php version.
sudo service apache restart
php -v
, , mbstring apache.
sudo phpenmod mbstring
sudo service apache restart
php manual php:
, .
:)