Update readme

Author: SergeyTsalkov

README.md

@@ -7,6 +7,7 @@ MeekroDB is:
 * A PHP MySQL library that lets you **get more done with fewer lines of code**, and **makes SQL injection 100% impossible**.
 * Google's #1 search result for "php mysql library" since 2013, with **thousands of deployments worldwide**.
 * A library with a **perfect security track record**. No bugs relating to security or SQL injection have ever been discovered.
+* Backwards and forwards-compatible, supporting all PHP versions **from PHP 5.3** all the way through the latest release of **PHP 8**.
 
 Installation
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