silverstripe-framework/docs/en/04_Changelogs/3.7.0.md

3.7.0 (unreleased)

SilverStripe 3.7 and PHP 7.2 and Object subclasses

For Project Code

SilverStripe 3.7 now supports PHP 7.2, which is exciting, but PHP 7.2 introduces an object keyword. To use it, you can replace any uses of Object with SS_Object in your own project code.

-class MyClass extends Object
+class MyClass extends SS_Object
{
	public function myFunction()
	{
-		$foo = Object::has_extension('MyExtension');
+		$foo = SS_Object::has_extension('MyExtension');
	}
}

You are also reliant on any SilverStripe modules directly using Object to upgrade their codebase. Matches for SS_Object in the module codebase will tell you it's been upgraded. A search for extends Object or Object:: isn't fool proof, but will give you an indication that the module still needs to be upgraded. If in doubt, check the module README.

For Module Authors

If you are publishing a 3.x-compatible module that directly references the Object class, we recommend that you replace all references to Object with SS_Object, and add the following line to your module's _config.php in order to support both current SilverStripe 3.x and SilverStripe 3.7 releases running on PHP 7.2:

// Ensure compatibility with PHP 7.2 ("object" is a reserved word),
// with SilverStripe 3.6 (using Object) and SilverStripe 3.7 (using SS_Object)
if (!class_exists('SS_Object')) class_alias('Object', 'SS_Object');

Don't forget to mention explicit PHP 7.2 and SilverStripe 3.7 compatibility in your module README.

Note that in SilverStripe 4.x, the Object class was deleted so there isn’t an SS_Object class there either (see https://docs.silverstripe.org/en/4/changelogs/4.0.0/)