I just did what was documented here but added in case they go away ever.
1 – get the installed packages
dpkg -l | grep php | tee packages.txt2 – get php 7
sudo apt install php7.3 php7.3-common php7.3-cli
3 – get the rest of the packages that you got in step 1
4 – uninstall php5
sudo apt-get purge php5*
5 – if you have fpm for web serving point all the things that used to point to
/var/run/php5-fpm.sock
to
/var/run/php/php7-fpm.sock