Setting the scene

WordPressCS currently has a minimum PHP requirement of PHP 5.4 and supports PHP_CodeSniffer 3.x (with a minimum of PHPCS 3.13.0).

PHP_CodeSniffer 3.x has a minimum PHP requirement of PHP 5.4.
PHP_CodeSniffer 4.0 (expected soon) will have a minimum PHP requirement of PHP 7.2.

Also keep in mind, that even though PHPCS 4.x will need PHP 7.2 or higher to run, it will still be able to analyse code which needs to run on older PHP versions.

The proposal

With the above in mind and considering that:

• The WordPress project has already dropped support for PHP < 7.2;
• We keep running into issues in CI with PHP 5.5;
• The fast majority of the users of WordPressCS do not use PHP < 7.2 anymore: https://packagist.org/packages/wp-coding-standards/wpcs/php-stats (only 0.6% of users still use PHP < 7.2)
• And setting up the CI scripts to test both PHPCS 3.x as well as 4.x against all their respective supported PHP versions adds additional complexity;

I'm proposing to drop support for PHP < 7.2 in the next minor of WordPressCS.

Any objections ?