Mistral AI Upgrade & Migration

Current State

!

npm list @mistralai/mistralai 2>/dev/null || echo 'not installed'

pip show mistralai 2>/dev/null | grep -E "^(Name|Version)" || echo 'not installed'

Overview

Guide for upgrading the Mistral AI SDK between major versions. The TypeScript SDK (

@mistralai/mistralai

Prerequisites

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

Instructions

Step 1: Check Versions

set -euo pipefail
# Current version
npm list @mistralai/mistralai 2>/dev/null

# Latest available
npm view @mistralai/mistralai version

# All versions
npm view @mistralai/mistralai versions --json | jq '.[-5:]'

# Python
pip show mistralai 2>/dev/null | grep Version

Step 2: Known Breaking Changes (v0.x to v1.x)

import MistralClient from '...'

import { Mistral } from '...'

new MistralClient(apiKey)

new Mistral({ apiKey })

client.chat(params)

client.chat.complete(params)

client.chatStream(params)

client.chat.stream(params)

for await (const chunk of stream)

for await (const event of stream)

.data

client.embeddings(params)

client.embeddings.create(params)

Step 3: Automated Migration Script

// scripts/migrate-mistral-v1.ts
import { readFileSync, writeFileSync } from 'fs';
import { glob } from 'glob';

const TRANSFORMS = [
  // Import statement
  {
    find: /import\s+MistralClient\s+from\s+['"]@mistralai\/mistralai['"]/g,
    replace: "import { Mistral } from '@mistralai/mistralai'",
  },
  // Constructor
  {
    find: /new\s+MistralClient\((\w+)\)/g,
    replace: 'new Mistral({ apiKey: $1 })',
  },
  // Chat method (careful: only top-level .chat(), not .chat.complete())
  {
    find: /\.chat\((?!\.)/g,
    replace: '.chat.complete(',
  },
  // Streaming
  {
    find: /\.chatStream\(/g,
    replace: '.chat.stream(',
  },
  // Embeddings
  {
    find: /\.embeddings\((?!\.)/g,
    replace: '.embeddings.create(',
  },
];

async function migrate() {
  const files = await glob('src/**/*.{ts,js}');
  let totalChanges = 0;

  for (const file of files) {
    let content = readFileSync(file, 'utf-8');
    let changes = 0;

    for (const { find, replace } of TRANSFORMS) {
      const newContent = content.replace(find, replace);
      if (newContent !== content) {
        changes++;
        content = newContent;
      }
    }

    if (changes > 0) {
      writeFileSync(file, content);
      console.log(`Migrated: ${file} (${changes} changes)`);
      totalChanges += changes;
    }
  }

  console.log(`\nTotal: ${totalChanges} changes across ${files.length} files`);
}

migrate();

Step 4: Upgrade Procedure

set -euo pipefail
# Create branch
git checkout -b upgrade/mistral-sdk-v1

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

# Upgrade
npm install @mistralai/mistralai@latest

# Ensure package.json has "type": "module"
node -e "const p=require('./package.json'); if(p.type!=='module') console.warn('WARNING: Add \"type\": \"module\" to package.json for ESM')"

# Run migration script
npx tsx scripts/migrate-mistral-v1.ts

# Verify
npm run typecheck
npm test

Step 5: Model Name Updates

Model names change over time. Update hardcoded references:

// Model alias mapping — update when models deprecate
const MODEL_ALIASES: Record<string, string> = {
  // Deprecated → Current
  'mistral-tiny': 'mistral-small-latest',
  'mistral-medium': 'mistral-small-latest', // Deprecated Q1 2025
  'open-mistral-7b': 'mistral-small-latest',
  'open-mixtral-8x7b': 'mistral-small-latest',

  // Current (no change needed)
  'mistral-small-latest': 'mistral-small-latest',
  'mistral-large-latest': 'mistral-large-latest',
  'codestral-latest': 'codestral-latest',
  'mistral-embed': 'mistral-embed',
};

function resolveModel(model: string): string {
  const resolved = MODEL_ALIASES[model];
  if (resolved && resolved !== model) {
    console.warn(`Model "${model}" is deprecated, using "${resolved}"`);
  }
  return resolved ?? model;
}

Step 6: Validation Tests

import { describe, it, expect } from 'vitest';
import { Mistral } from '@mistralai/mistralai';

describe('SDK Upgrade Validation', () => {
  it('should import Mistral correctly', () => {
    expect(Mistral).toBeDefined();
    expect(typeof Mistral).toBe('function');
  });

  it('should construct client', () => {
    const client = new Mistral({ apiKey: 'test-key' });
    expect(client.chat).toBeDefined();
    expect(client.chat.complete).toBeDefined();
    expect(client.chat.stream).toBeDefined();
    expect(client.embeddings).toBeDefined();
    expect(client.embeddings.create).toBeDefined();
    expect(client.models).toBeDefined();
    expect(client.models.list).toBeDefined();
  });
});

Step 7: Rollback

set -euo pipefail
# Quick rollback
npm install @mistralai/mistralai@0.5.0 --save-exact
git checkout -- src/  # Restore pre-migration code
npm test

# Or just revert the branch
git checkout main
git branch -D upgrade/mistral-sdk-v1

Error Handling

ERR_REQUIRE_ESM

Mistral is not a constructor

import { Mistral }

.chat is not a function

.chat.complete()

Resources

• TypeScript SDK Releases
• Python SDK Releases
• Changelog
• Models Deprecation

Output

• Updated SDK to latest version
• Automated code migration applied
• Model name references updated
• Test suite passing after upgrade
• Rollback procedure documented