Help with simplexml / libxml

The owner of the business I work for just upgraded one of our servers to 16.04, and since then, simplexml isn’t working.

The error I see in the apache logs is:

Uncaught Error: Call to undefined function simplexml_load_string()

I’m seeing the following when I run php -i:

php: /usr/local/lib/ no version information available (required by php)

/usr/local/lib/ is a symlink to in the same directory (/usr/local/lib).

According to webmin, the package currently installed is

I’m not a linux guru by any means, but our PHP code needs simplexml, so I need to get this fixed.

Can anyone give any input on how to fix this?