customerio-upgrade-migration

# Customer.io Upgrade & Migration

## Overview
Plan and execute Customer.io SDK upgrades and migrations safely.

## Prerequisites
- Current SDK version identified
- Test environment available
- Rollback plan prepared

## Instructions

### Step 1: Assess Current State
```bash
#!/bin/bash
# assess-customerio.sh

echo "=== Customer.io SDK Assessment ==="

# Node.js SDK
echo "Node.js SDK:"
npm list @customerio/track 2>/dev/null || echo "Not installed"
npm list customerio-node 2>/dev/null || echo "Legacy SDK not installed"

# Python SDK
echo -e "\nPython SDK:"
pip show customerio 2>/dev/null || echo "Not installed"

# Check for latest versions
echo -e "\nLatest versions available:"
npm view @customerio/track version 2>/dev/null
pip index versions customerio 2>/dev/null | head -1
```

### Step 2: Review Breaking Changes
```markdown
## Customer.io SDK Changelog Review

### @customerio/track (Node.js)
- v1.x -> v2.x: Updated to ESM modules
- v2.x -> v3.x: Changed region configuration

### customerio (Python)
- v1.x -> v2.x: Async client support added

### API Changes
- Check https://customer.io/docs/changelog/
```

### Step 3: Create Migration Plan
```typescript
// migration-plan.ts
interface MigrationPlan {
  currentVersion: string;
  targetVersion: string;
  breakingChanges: string[];
  codeChanges: CodeChange[];
  testCases: string[];
  rollbackProcedure: string[];
  timeline: Timeline;
}

const migrationPlan: MigrationPlan = {
  currentVersion: '1.2.0',
  targetVersion: '2.0.0',
  breakingChanges: [
    'Region now required in constructor',
    'Event data structure changed',
    'Error types updated'
  ],
  codeChanges: [
    {
      file: 'lib/customerio.ts',
      before: `new TrackClient(siteId, apiKey)`,
      after: `new TrackClient(siteId, apiKey, { region: RegionUS })`
    },
    {
      file: 'lib/customerio.ts',
      before: `client.track(userId, eventName, data)`,
      after: `client.track(userId, { name: eventName, data })`
    }
  ],
  testCases: [
    'I