The php-apcu-bc
package provides a backwards compatibility layer from apcu -> apc, and is reuqired for some older PHP code bases (e.g. Yii 1). The package is not (yet) available in the Ubuntu 16.04 repos. To install it, use php-pear:
sudo apt-get install php-dev php-pear
sudo pecl install apcu_bc-beta
Then edit /etc/php/7.0/apache2/php.ini
and add the following at the end of the file: