apt-get purge php7* apt-get purge php7*-common apt-get purge php8* apt-get purge php8*-common apt-get install php5.6 a2dismod php7 a2dismod php8 a2enmod php8
apt-get purge php7* apt-get purge php7*-common apt-get purge php8* apt-get purge php8*-common apt-get install php5.6 a2dismod php7 a2dismod php8 a2enmod php8