(PHP 7, PHP 8)
 Throwable is the base interface for any object that
 can be thrown via a throw statement, including
 Error  and Exception .
 
Note:
PHP classes cannot implement the Throwable interface directly, and must instead extend Exception .
| Version | Description | 
|---|---|
| 8.0.0 | Throwable implements Stringable now. | 
I wrote a simple script that prints out the Throwable and Exception tree for every PHP version.
You can find this script here:
https://gist.github.com/mlocati/249f07b074a0de339d4d1ca980848e6a 
And its output is here:
https://3v4l.org/sDMsv try {
// Code that may throw an Exception or Error.
} catch (Throwable $t) {
// Executed only in PHP 7, will not match in PHP 5.x
} catch (Exception $e) {
// Executed only in PHP 5.x, will not be reached in PHP 7
}
interface MyPackageThrowable extends Throwable {}
class MyPackageException extends Exception implements MyPackageThrowable {}
throw new MyPackageException();