Right now we have a few issues scattered across multiple repositories, so I figured I'd create one to combine them all.

To-do

• Update requirements on the wp-cli.org website.

Expected breaking changes in v3.0.0

• Current issues in the 3.0.0 milestone

PHP version bump

In our next release, we’ll bump the minimum PHP version to 7.2.24+.

With this bump we can:

• Drop support for older WordPress versions, likely WordPress 4.8 and below
  • According to https://make.wordpress.org/core/handbook/references/php-compatibility-and-wordpress-versions/, WordPress 4.9 is the first version to support PHP 7.2
  • We can check whether older versions like WordPress 4.7 still work ok with that version though. There might be some wiggle room.
  • Most notably, we'll stop testing the WordPress 3.7 & PHP 5.6 combination
  • Consider increasing minimum supported WordPress version #5705
• Remove a lot of old compatibility code throughout the codebase
  • For example the wp-settings-cli.php file in wp-cli/wp-cli, which is for WP < 4.6
• Slowly adopt new language features such as new type declarations, null coalescing operator, and much more
  • Keep public APIs as-is to avoid unnecessary breaking changes
  • Do this only where it makes sense
• Remove the https://github.com/wp-cli/process fork again
• Use PHPStan 1.x
  • Add PHPStan support wp-cli-tests#203
• Use the oldest still maintained PHPUnit version, PHPUnit 8, requires PHP 7.2, so we'll be able to use that
• Re-Add roave/security-advisories after PHP requirement bump #6087

To do this bump:

1. Update test matrix in https://github.com/wp-cli/.github to remove anything below PHP 7.2. Add new entries with PHP 7.2 & WP 4.9 or so.
2. Bump requirement in wp-cli/wp-cli-bundle
   • https://github.com/wp-cli/wp-cli-bundle/blob/44e61272f9deaa0825165dd5472d6c601d0ec85c/composer.json#L11
   • https://github.com/wp-cli/wp-cli-bundle/blob/44e61272f9deaa0825165dd5472d6c601d0ec85c/composer.json#L53
   • ... and many more places
3. Bump requirement in wp-cli/wp-cli

   • wp-cli/composer.json

     Line 11 in 3ca317a

     "php": "^5.6 || ^7.0 || ^8.0",

   • wp-cli/manifest.json

     Line 2 in 3ca317a

     "requires_php": "5.6.0"

     • With this, wp cli update will not show you the new version if you're not on PHP 7.2+

   • wp-cli/php/boot-fs.php

     Line 10 in 3ca317a

     if ( version_compare( PHP_VERSION, '5.6.0', '<' ) ) {

   • ... and many more places
4. Bump requirements in all the packages
5. ... and probably many more steps