Mistral AI Upgrade & Migration

Overview

Guide for upgrading Mistral AI SDK versions and handling breaking changes.

Prerequisites

• Current Mistral AI SDK installed
• Git for version control
• Test suite available
• Staging environment

Instructions

Step 1: Check Current Version

# Node.js SDK
npm list @mistralai/mistralai
npm view @mistralai/mistralai versions --json | jq '.[-5:]'

# Python SDK
pip show mistralai
pip index versions mistralai 2>/dev/null || pip install mistralai==

# Check for outdated
npm outdated @mistralai/mistralai

Step 2: Review Changelog

# Check GitHub releases
open https://github.com/mistralai/client-js/releases
open https://github.com/mistralai/client-python/releases

# Check npm changelog
npm info @mistralai/mistralai

Step 3: Create Upgrade Branch

# Create feature branch
git checkout -b upgrade/mistral-sdk-vX.Y.Z

# Backup current lock file
cp package-lock.json package-lock.json.bak

# Upgrade SDK
npm install @mistralai/mistralai@latest

# Or specific version
npm install @mistralai/mistralai@1.2.0

# Check what changed
npm diff @mistralai/mistralai

Step 4: Handle Breaking Changes

Common Migration Patterns:

Import Changes (v0.x to v1.x)

// Before (v0.x)
import MistralClient from '@mistralai/mistralai';
const client = new MistralClient(apiKey);

// After (v1.x)
import Mistral from '@mistralai/mistralai';
const client = new Mistral({ apiKey });

Method Changes

// Before
const response = await client.chat(params);

// After (v1.x)
const response = await client.chat.complete(params);

Streaming Changes

// Before
const stream = await client.chatStream(params);
for await (const chunk of stream) { ... }

// After (v1.x)
const stream = await client.chat.stream(params);
for await (const event of stream) {
  const chunk = event.data;
  ...
}

Step 5: Run Tests

# Type check
npm run typecheck

# Unit tests
npm test

# Integration tests
MISTRAL_API_KEY=$MISTRAL_API_KEY_TEST npm run test:integration

# Compare outputs
npm run test -- --updateSnapshot # if using snapshots

Step 6: Create Migration Script

// scripts/migrate-mistral.ts
import { readFileSync, writeFileSync } from 'fs';
import { glob } from 'glob';

const MIGRATIONS: Array<{ pattern: RegExp; replacement: string }> = [
  // Import statement
  {
    pattern: /import MistralClient from '@mistralai\/mistralai'/g,
    replacement: "import Mistral from '@mistralai/mistralai'",
  },
  // Client instantiation
  {
    pattern: /new MistralClient\((\w+)\)/g,
    replacement: 'new Mistral({ apiKey: $1 })',
  },
  // Chat method
  {
    pattern: /\.chat\(/g,
    replacement: '.chat.complete(',
  },
  // Streaming method
  {
    pattern: /\.chatStream\(/g,
    replacement: '.chat.stream(',
  },
];

async function migrate() {
  const files = await glob('src/**/*.{ts,js}');

  for (const file of files) {
    let content = readFileSync(file, 'utf-8');
    let modified = false;

    for (const { pattern, replacement } of MIGRATIONS) {
      if (pattern.test(content)) {
        content = content.replace(pattern, replacement);
        modified = true;
      }
    }

    if (modified) {
      writeFileSync(file, content);
      console.log(`Migrated: ${file}`);
    }
  }
}

migrate();

Step 7: Document Changes

## Mistral SDK Upgrade: v0.x → v1.x

### Breaking Changes Applied
1. Updated import statement
2. Changed client instantiation
3. Updated chat method calls
4. Modified streaming interface

### Files Modified
- src/mistral/client.ts
- src/services/chat.ts
- tests/mistral.test.ts

### Testing
- [ ] Unit tests pass
- [ ] Integration tests pass
- [ ] Staging deployment verified
- [ ] Performance benchmarked

### Rollback
```bash
npm install @mistralai/mistralai@0.x.x
git checkout -- src/

## Output
- Updated SDK version
- Fixed breaking changes
- Passing test suite
- Documented rollback procedure

## Version Compatibility

| SDK Version | Node.js | API Version | Notable Changes |
|-------------|---------|-------------|-----------------|
| 1.x | 18+ | Latest | New client interface |
| 0.5.x | 16+ | v1 | Stable, legacy |
| 0.4.x | 16+ | v1 | Streaming improvements |

## Error Handling

| Error After Upgrade | Cause | Solution |
|---------------------|-------|----------|
| Import error | Changed exports | Update import statement |
| Type errors | Interface changes | Update types |
| Runtime error | Method signature changed | Check migration guide |
| Test failures | Response format changed | Update assertions |

## Examples

### Deprecation Handling
```typescript
// Monitor for deprecation warnings
if (process.env.NODE_ENV === 'development') {
  process.on('warning', (warning) => {
    if (warning.name === 'DeprecationWarning') {
      console.warn('[Mistral SDK]', warning.message);
    }
  });
}

Gradual Migration with Feature Flag

const USE_NEW_SDK = process.env.MISTRAL_SDK_V1 === 'true';

async function chat(messages: Message[]): Promise<string> {
  if (USE_NEW_SDK) {
    // New SDK interface
    const client = new Mistral({ apiKey: process.env.MISTRAL_API_KEY });
    const response = await client.chat.complete({ model, messages });
    return response.choices?.[0]?.message?.content ?? '';
  } else {
    // Legacy interface
    const client = new MistralClient(process.env.MISTRAL_API_KEY);
    const response = await client.chat({ model, messages });
    return response.choices?.[0]?.message?.content ?? '';
  }
}

Rollback Procedure

# Quick rollback
npm install @mistralai/mistralai@0.5.0 --save-exact

# Verify rollback
npm list @mistralai/mistralai
npm test

Resources

• Mistral AI Changelog
• Mistral AI Migration Guide

Next Steps

For CI integration during upgrades, see

mistral-ci-integration

.