whether $x is greater than zero. If it is not, an AssertionError exception is thrown with the message "$x must be greater than zero". The throws keyword, on the other hand, is used to specify which exceptions a function or method can throw. This can be helpful for documenting your code and making it easier for other developers to understand how your functions and methods behave. For example:function divide(int $a, int $b): int { if ($b === 0) { throw new DivisionByZeroError('Cannot divide by zero'); } return $a / $b; }In this example, the divide() function uses the throws keyword to specify that it can throw a DivisionByZeroError exception if the second argument is zero. Overall, the assert() function and the throws keyword are useful tools for handling errors and exceptions in PHP, and can help you write more reliable and robust code. Support for enumerations Support for enumerations was one of the most prominent features of PHP 8.1. Enums allow developers to programmatically enforce states in their codebase. Below is an example of an enum: <?php namespace App\Enums; enum InvoiceStatus: string { case draft = 'draft'; case pending = 'pending'; case paid = 'paid'; case expired = 'expired'; } Other PHP 8.1 features Support for `read-only` properties was added. After the introduction of array unpacking in PHP 7.4 with consecutive numbered keys, PHP 8.1 introduced support for array unpacking with string keys. PHP 8.1 added support for using `new` in initializers. A new syntax was added for creating callables. PHP 8.1 brought support for Pure Intersection Types, after in the introduction of union types in PHP 8.0. PHP 8.2 PHP 8.2 includes a number of new features and improvements. Here are some of the main ones: Union Types: Union types allow you to specify that a function or method parameter can accept multiple types, separated by the "|" symbol. This can help to improve type safety and reduce the need for type juggling. Nullsafe Operator: The nullsafe operator (?->) allows you to chain method calls without having to check for null values at each step. This can help to reduce the need for null checks and make your code more concise. Match Expression: The match expression allows you to perform pattern matching on values, similar to a switch statement in other languages. This can be a more concise and expressive way to handle multiple conditions. Improved Type Variance: PHP