PHP 7 simpleXML

For all those using Ubuntu with ppa:ondrej/php PPA this will fix the problem:

apt install php7.0-mbstring php7.0-zip php7.0-xml

(see https://launchpad.net/~ondrej/+archive/ubuntu/php)

Thanks @Alexandre Barbosa for pointing this out!

EDIT 20160423:

One-liner to fix this issue:

sudo add-apt-repository -y ppa:ondrej/php && sudo apt update && sudo apt install -y php7.0-mbstring php7.0-zip php7.0-xml

(this will add the ppa noted above and will also make sure you always have the latest php. We use Ondřej's PHP ppa for almost two years now and it's working like charm)

I had the same problem and I'm using Ubuntu 15.10.

In my case, to solve this issue, I installed the package php7.0-xml using the Synaptic package manager, which include SimpleXml. So, after restart my Apache server, my problem was solved. This package came in the Debian version and you can find it here: https://packages.debian.org/sid/php7.0-xml.

For Alpine (in docker), you can use apk add php7-simplexml.

If that doesn't work for you, you can run apk add --no-cache php7-simplexml. This is in case you aren't updating the package index first.

For Ubuntu 14.04 with

PHP 7.0.13-1+deb.sury.org~trusty+1 (cli) ( NTS )

sudo apt-get install php-xml

worked for me.