Add a “What’s changed?” guide for Apps‑Engine contributors

Hi team

While exploring the Apps Engine and preparing for local development, I noticed that there isn’t a centralized way for contributors to quickly understand what has changed between versions of the Apps Engine API.

At the moment, keeping track of changes requires going through multiple sources such as PRs, release notes, and issues, which can be time-consuming and sometimes unclear.

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Current Challenges

• Changes to the Apps Engine (new methods, deprecations, behavior updates) are spread across PRs and discussions
• It’s difficult to distinguish breaking changes vs additive changes
• Contributors often need to manually test or dig through commits to understand what changed

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Why this matters

The Apps Engine is continuously evolving, and more developers are building custom apps on top of it.

Without a clear summary of changes:

• Contributors spend extra time understanding version differences
• Upgrading existing apps becomes harder and error-prone
• There is a risk of relying on deprecated or modified APIs

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Suggested Improvement

Introduce a dedicated “What’s Changed?” guide for the Apps Engine, for example:

• A file like WHAT_CHANGED_APPS_ENGINE.md or a dedicated docs section

• Organized by version (e.g., “Changes since v1.50”)

• Clearly categorized into:

  • Breaking changes
  • New features
  • Behavior updates

Additionally, this guide could be:

• Maintained alongside releases
• Linked from the main Apps Engine README
• Written in a concise, developer-friendly format

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Expected Impact

• Faster understanding of API changes
• Easier upgrades for existing apps
• Improved developer experience for both new and existing contributors

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If this aligns with the project direction, I’d be happy to help draft an initial version or propose a structure for this guide

Thanks!

Start by reviewing the Apps Engine README and the existing PRs, release notes, and issues that describe API changes. Draft a WHAT_CHANGED_APPS_ENGINE.md guide organized by version, separating breaking changes, new features, and behavior updates, then link it from the Apps Engine README. Done means contributors can use the guide to understand version differences and upgrade impacts.