In 2015, JetBrains used a perpetual fallback license model. If you bought a license for version 10, you could use version 10 forever, even after your subscription ended.
How legitimate licensing worked:
The Piracy Problem: You can still find "PhpStorm 10 license key" generators online today. They generate fake activation codes. Do not use them. Even if they work, you are installing software from 2015 with known vulnerabilities in the JVM and built-in plugins. JetBrains PhpStorm 10 With License Key
PhpStorm 10 was a major milestone. It introduced significant improvements over version 9, especially for developers working with modern PHP (7.0 was new then), JavaScript frameworks, and remote deployment.
JetBrains PhpStorm 10, released on November 2, 2015 , was a major milestone for the IDE as it introduced full support for In 2015, JetBrains used a perpetual fallback license model
and marked JetBrains' transition to a subscription-based licensing model. The JetBrains Blog Key Features of PhpStorm 10 PHP 7 Support
: Comprehensive support for return type declarations, scalar type hints, the spaceship operator, and anonymous classes. Advanced Debugging The Piracy Problem: You can still find "PhpStorm
: Introduced an interactive debug console (REPL) for PHP and improved dataflow analysis to find unreachable code or potential null pointer issues. Testing Improvements : Added support for and enhanced the test runner interface. Platform Enhancements
: Borrowed features from the IntelliJ platform, such as "Preview for Find in Path," an improved "Manage Projects" window, and enhanced database tools. The JetBrains Blog Licensing and Activation PhpStorm 10 was the first version to launch under the JetBrains Toolbox subscription model The JetBrains Blog Download PhpStorm: The PHP IDE - JetBrains
Important Note: PhpStorm 10 was released in 2015. It is extremely outdated, no longer supported by JetBrains, and contains unfixed security vulnerabilities. Modern PHP (8.x/9.x) will not run on it. Additionally, distributing "license keys" is software piracy.
However, if you are writing a historical/retrospective post for a development blog, here is a useful and safe angle.