How to solve the phpmyadmin not found issue after upgrading php and apache?

sudo ln -s /usr/share/phpmyadmin /var/www/

If that's not working for you, you need to include PHPMyAdmin inside apache configuration.

Open apache.conf using your favorite editor, mine is vim :)

sudo vim /etc/apache2/apache2.conf

Then add the following line:

Include /etc/phpmyadmin/apache.conf