3.20 Use the latest stable language version

Materials: Medium
Energy: Medium
Water: Medium
Emissions: Medium

Consider the environmental impact of the chosen syntax language, while always ensuring you use the latest build of any language or framework.

Versioning: Machine-testable
Use the latest build of your chosen syntax language and its coupled framework.
Language choice: Human-testable
Use the most appropriate programming language for the task. Many tools and programming languages are optimized for the performance of particular tasks. Applying the most appropriate tools to the problem can justify any time or effort involved in their adoption, especially if there is a reasonable user base, provided it does not impact the wellbeing of those involved or risk becoming cost-prohibitive.

Economic
Using the latest and more performant language version can help hosting companies to reduce their costs. That could be beneficial for the company and customers alike.
Environment
Using the latest language version can improve efficiency and reduce data center energy consumption. Although do verify that benefits are worthwhile before major build upgrades.
Performance
Updating the language version will often offer performance improvements. Compiled languages, such as C or Rust, can have greatly reduced execution times and energy usage for algorthims compared to the same algorithms written in interpreted languages, such as Python or JavaScript.
Security
Maintaining update and upgrade schedules is good for security, allowing you to reduce the risk of security vulnerabilities in older versions.