PHP 7.3: What's New and Changed

PHP 7.3 brings several Quality-of-Life improvements to PHP. Major improvements include the flexible Heredoc/Nowdoc syntax, a high-resolution timer, is_countable() function to help with the numerous PHP notices raised because PHP 7.2 deprecated using count() function on uncountable values, list() improvements, and new Argon2ID password hashing algorithm.

This version does not bring major syntax improvements to the table. It cleans up a lot of legacy aliased functions, and brings modern password hashing algorithm in continuation of the Argon2I introduced in PHP 7.2.

Except for the flexible heredoc/nowdoc syntax and improvements in list() construct supporting references, the rest of the major changes are available as polyfills.