How to Switch PHP Version in Laravel Valet between PHP 7.1 and PHP 5.6

ValetSwitchPHP.md

Valet switch PHP version with these commands

Install PHP 5.6 and switch Valet to PHP 5.6

valet stop
brew unlink php71
brew install php56
brew install php56-mcrypt
brew link php56
valet start

Then to switch back to PHP 7.1 it is as simple as:

valet stop
brew unlink php56
brew link php71
valet start

Then to switch to PHP 5.6:

valet stop
brew unlink php71
brew link php56
valet start

For those who're using Ubuntu Valet (unofficial), after installing certain version of php, you just need to stop the valet before switching the php version.

valet stop

#choose your preffered php (you need to install php first)
update-alternatives --config php

valet start

For me, php7.2 already pre-installed in my Ubuntu 18.04. So I installed php5.6, php5.6-fpm and php5.6-cli before I can switch between my preferred php version.