Changelog Maintenance

When to use this skill

• Before release: organize changes before shipping a version
• Continuous: update whenever significant changes occur
• Migration guide: document breaking changes

Instructions

Step 1: Keep a Changelog format

CHANGELOG.md:

# Changelog

All notable changes to this project will be documented in this file.

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

## [Unreleased]

### Added
- New user profile customization options
- Dark mode support

### Changed
- Improved performance of search feature

### Fixed
- Bug in password reset email

## [1.2.0] - 2025-01-15

### Added
- Two-factor authentication (2FA)
- Export user data feature (GDPR compliance)
- API rate limiting
- Webhook support for order events

### Changed
- Updated UI design for dashboard
- Improved email templates
- Database query optimization (40% faster)

### Deprecated
- `GET /api/v1/users/list` (use `GET /api/v2/users` instead)

### Removed
- Legacy authentication method (Basic Auth)

### Fixed
- Memory leak in background job processor
- CORS issue with Safari browser
- Timezone bug in date picker

### Security
- Updated dependencies (fixes CVE-2024-12345)
- Implemented CSRF protection
- Added helmet.js security headers

## [1.1.2] - 2025-01-08

### Fixed
- Critical bug in payment processing
- Session timeout issue

## [1.1.0] - 2024-12-20

### Added
- User profile pictures
- Email notifications
- Search functionality

### Changed
- Redesigned login page
- Improved mobile responsiveness

## [1.0.0] - 2024-12-01

Initial release

### Added
- User registration and authentication
- Basic profile management
- Product catalog
- Shopping cart
- Order management

[Unreleased]: https://github.com/username/repo/compare/v1.2.0...HEAD
[1.2.0]: https://github.com/username/repo/compare/v1.1.2...v1.2.0
[1.1.2]: https://github.com/username/repo/compare/v1.1.0...v1.1.2
[1.1.0]: https://github.com/username/repo/compare/v1.0.0...v1.1.0
[1.0.0]: https://github.com/username/repo/releases/tag/v1.0.0

Step 2: Semantic Versioning

Version number: MAJOR.MINOR.PATCH

Given a version number MAJOR.MINOR.PATCH, increment:

MAJOR (1.0.0 → 2.0.0): Breaking changes
  - API changes break existing code
  - Example: adding required parameters, changing response structure

MINOR (1.1.0 → 1.2.0): Backward-compatible features
  - Add new features
  - Existing functionality continues to work
  - Example: new API endpoints, optional parameters

PATCH (1.1.1 → 1.1.2): Backward-compatible bug fixes
  - Bug fixes
  - Security patches
  - Example: fixing memory leaks, fixing typos

Examples:

• 1.0.0 → 1.0.1: bug fix
• 1.0.1 → 1.1.0: new feature
• 1.1.0 → 2.0.0: Breaking change

Step 3: Release Notes (user-friendly)

# Release Notes v1.2.0
**Released**: January 15, 2025

## 🎉 What's New

### Two-Factor Authentication
You can now enable 2FA for enhanced security. Go to Settings > Security to set it up.

![2FA Setup](https://example.com/images/2fa.png)

### Export Your Data
We've added the ability to export all your data in JSON format. Perfect for backing up or migrating your account.

## ✨ Improvements

- **Faster Search**: Search is now 40% faster thanks to database optimizations
- **Better Emails**: Redesigned email templates for a cleaner look
- **Dashboard Refresh**: Updated UI with modern design

## 🐛 Bug Fixes

- Fixed a bug where password reset emails weren't being sent
- Resolved timezone issues in the date picker
- Fixed memory leak in background jobs

## ⚠️ Breaking Changes

If you're using our API:

- **Removed**: Basic Authentication is no longer supported
  - **Migration**: Use JWT tokens instead (see [Auth Guide](docs/auth.md))

- **Deprecated**: `GET /api/v1/users/list`
  - **Migration**: Use `GET /api/v2/users` with pagination

## 🔒 Security

- Updated all dependencies to latest versions
- Added CSRF protection to all forms
- Implemented security headers with helmet.js

## 📝 Full Changelog

See [CHANGELOG.md](CHANGELOG.md) for complete details.

---

**Upgrade Instructions**: [docs/upgrade-to-v1.2.md](docs/upgrade-to-v1.2.md)

Step 4: Breaking Changes migration guide

# Migration Guide: v1.x to v2.0

## Breaking Changes

### 1. Authentication Method Changed

**Before** (v1.x):
\`\`\`javascript
fetch('/api/users', {
  headers: {
    'Authorization': 'Basic ' + btoa(username + ':' + password)
  }
});
\`\`\`

**After** (v2.0):
\`\`\`javascript
// 1. Get JWT token
const { accessToken } = await fetch('/api/auth/login', {
  method: 'POST',
  body: JSON.stringify({ email, password })
}).then(r => r.json());

// 2. Use token
fetch('/api/users', {
  headers: {
    'Authorization': 'Bearer ' + accessToken
  }
});
\`\`\`

### 2. User List API Response Format

**Before** (v1.x):
\`\`\`json
{
  "users": [...]
}
\`\`\`

**After** (v2.0):
\`\`\`json
{
  "data": [...],
  "pagination": {
    "page": 1,
    "limit": 20,
    "total": 100
  }
}
\`\`\`

**Migration**:
\`\`\`javascript
// v1.x
const users = response.users;

// v2.0
const users = response.data;
\`\`\`

## Deprecation Timeline

- v2.0 (Jan 2025): Basic Auth marked as deprecated
- v2.1 (Feb 2025): Warning logs for Basic Auth usage
- v2.2 (Mar 2025): Basic Auth removed

Output format

CHANGELOG.md             # Developer-facing detailed log
RELEASES.md              # User-facing release notes
docs/migration/
  ├── v1-to-v2.md        # Migration guide
  └── v2-to-v3.md

Constraints

Required rules (MUST)

1. Reverse chronological: latest version at the top
2. Include dates: ISO 8601 format (YYYY-MM-DD)
3. Categorize entries: Added, Changed, Fixed, etc.

Prohibited items (MUST NOT)

1. No copying Git logs: write from the user's perspective
2. Vague wording: "Bug fixes", "Performance improvements" (be specific)

Best practices

1. Keep a Changelog: follow the standard format
2. Semantic Versioning: consistent version management
3. Breaking Changes: provide a migration guide

References

• Keep a Changelog
• Semantic Versioning

Metadata

Version

• Current version: 1.0.0
• Last updated: 2025-01-01
• Compatible platforms: Claude, ChatGPT, Gemini

Tags

#changelog #release-notes #versioning #semantic-versioning #documentation

Examples

Example 1: Basic usage

Example 2: Advanced usage