PhpStorm provides stubs for extension classes through stub classes which are loaded from a custom repository: https://github.com/JetBrains/phpstorm-stubs. The stubs for PECL extensions are community-driven and need to be updated manually when changes to the respective extension occur. Since there will be a few new classes and methods in 1.6.0, we could update these stubs to reflect changes in 1.6.