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

ValetSwitchPHP.md

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

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

What should I do on Ubuntu? please help me.

I needed to do a few more things to get it working:

# Update global composer packages
$ composer global update

# Reinstall Valet
$ valet install

In Homebrew ^1.5 a lot of PHP extensions were removed, causing brew install php56-mcrypt not to work anymore.
See the official announcement.
Luckily, mcrypt seems included in the newer formula for php@5.6

Other extensions can be installed with PECL. It looks like you need to do this every time you switch between versions though.

pecl uninstall -r imagick
pecl install imagick

Just to add to @kjbrum extra steps - unless you use valet plus, you may also have to edit your ~/.composer/composer.json file before you run composer global update.

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.

the problem is, if I'm on php 5.6 and want to switch to php 7.1, Valet fails:

PHP Parse error:  syntax error, unexpected '->' (T_OBJECT_OPERATOR) in /Users/x/.composer/vendor/tightenco/collect/src/Collect/Support/Collection.php on line 179

so can't stop Valet before php change..

Had the same thing, had to remove the global composer.lock file and vendor directory, and then re-required it.

$ rm -rf ~/.composer/composer.lock ~/.composer/vendor
$ composer global req laravel/valet

It works for me: https://gist.github.com/altynbek07/2147e48ea1df9145a803c8245f5dc130

on Ubuntu or linux, put this in your .profile

#switch php version
switch-php() {
    valet stop
    sudo update-alternatives --set php /usr/bin/php$1
    rm -f ~/.valet/valet.sock
    valet install
}

then use it as switch-php 7.1 or switch-php 7.4

One liner here, simply type this in your terminal

valet use php@7.2

One liner here, simply type this in your terminal

valet use php@7.2

Aweeesome! Thank you for sharing it! 🚀

you can use phpmon

brew tap nicoverbruggen/homebrew-cask
brew install --cask phpmon

I had to do
valet use php@7.4 --force
without it, it only changed the cli, and phpinfo in the browser showed 8.0