WordPress kept telling me that my version of PHP was too old, so I upgraded. I basically followed this tutorial: Upgrade/Installation guide for PHP 7.4 on Ubuntu and Debian. Here is the summary:
sudo add-apt-repository ppa:ondrej/php sudo apt-get update sudo apt-get install php7.4
However, I ran into a couple of issues. First, Apache didn’t pick up the new version automatically (duh!). I fixed it by removing and disabling the old version(s) of PHP, and enabling the new version:
sudo apt-get remove php7.0 sudo a2dismod php7.0 sudo a2enmod php7.4 sudo systemctl restart apache2
I learned about a2endmod from this other tutorial Upgrade PHP version to PHP 7.4 on Ubuntu.
And that’s it, WordPress now says I’m doing a great job!