Readonly clones, #[Override], and json_validate: what’s new in PHP 8.3

PHP 8.3 is coming on November 23, 2023. Let’s take a look at what’s new; from cloning readonly properties to json_validate and stack overflow detection. Timestamps 00:00 Intro 00:21 Cloning and overwriting readonly properties and classes 02:02 Readonly anonymous classes 02:05 Typed class constants 02:07 Dynamic class constant access 02:12 json_validate 02:33 Randomizer additions 02:48 Negative array index breaking change 03:26 The #[Override] attribute 04:18 Stack overflow detection 04:40 Other small deprecations and changes If you want to read about all the small deprecations and changes, like DateTime exception changes, changes to the range() function, static properties in traits, and more, head over to to read all about it.