Install PHP 7.1 on a Mac that Still Runs OSX 10.11 El Capitan
Open a terminal and run. Also, everything you need to know about this package is online at https://php-osx.liip.ch/.
curl -s https://php-osx.liip.ch/install.sh | bash -s 7.1
This package installs the PHP 7(in this case, 7.1) on OSX 10.11 (aka El Capitan) in /usr/local/php5. Yes, that looks like an odd place to install PHP 7.1, but it works.
Next, add the directory that holds the binary to your path.
To make this permanent, you can add
export PATH=/usr/local/php5/bin:$PATH to ~/.profile and relaunch your terminal. If you happen to use iTerm 2, you may need to add this command to