Backwards-compatibility in Cloudflare Workers

Cloudflare Workers is a serverless platform that runs code in 250+ cities worldwide, with a policy that changes to the Workers Runtime must never break an application live in production. This policy differs from traditional server platforms where developers maintain their own stack and decide when to upgrade. In the case of Cloudflare Workers, developers have no control over runtime upgrades, making it crucial for these updates to never break anything. However, sometimes fixes are needed that could potentially break applications. To address this issue, Cloudflare introduced "compatibility dates" where developers can opt into backwards-incompatible fixes by setting a compatibility date. This allows the platform to maintain strict compatibility while still allowing necessary changes and improvements.