Hi,

The default PHP and phpMyAdmin packages are in the ubuntu repos, which are enabled on your Droplet. When you installed that PPA, it was set as a higher priority than the default repos so that its packages are installed instead.

One option would be removing the PPA using ppa-purge which will gracefully downgrade the packages to those of the default repos. Keep in mind however that if you're downgrading to a PHP version that is much older than what you currently have, your configs might not be compatible with it, and you might have to adjust them accordingly.

First, install ppa-purge:

sudo apt-get install ppa-purge

Then, remove the ppa:ondrej/php PPA:

sudo ppa-purge ppa:ondrej/php

If you only want to remove the PPA without affecting any installed packages, however, you can simply run the add-apt-repository command again but with the --remove flag:

sudo apt-add-repository --remove ppa:ondrej/php

Finally, as with any other change to the list of apt repositories on your system, run apt-get update so that apt's repo cache matches the updated list.

sudo apt-get update