How to Update AWS CDK: CLI, Dependencies & Fixing Version Mismatches

Maintaining the AWS Cloud Development Kit (CDK) is crucial because AWS releases updates almost weekly. While frequent updates bring new L2 constructs and bug fixes, they often lead to the dreaded Version Mismatch error where your global CLI doesn't match your project dependencies.

In this guide, we won't just run a generic update command. We will look at how to synchronize your environment safely, handle package.json dependencies, and fix breaking changes without stalling your pipeline.

Check Your Current CDK Version

Before running any update commands, you need to know the discrepancy between your global CLI and your project's core library.

Run this command in your terminal:

cdk --version

If you see a specific version output like 2.100.0, that is your Global CLI version. However, your project might be running on an older version defined in your package.json.

Pro Tip: If you want to check the version without relying on the global installation (which mimics how CI/CD pipelines work), use npx:

npx aws-cdk --version

How to Update AWS CDK CLI (Global)

The CDK Command Line Interface (CLI) is the tool you use to synthesize and deploy stacks.

Using npm (Node Package Manager)

To update the tool globally on your machine:

npm install -g aws-cdk@latest

Using Yarn

If you manage global packages with Yarn:

yarn global upgrade aws-cdk

Warning: Updating the global CLI is often where problems start. If your global CLI is version 2.110.0 but your project's package.json is stuck at 2.80.0, you will likely encounter an error during synthesis. This is why updating the project dependencies is equally important.

Updating Project Dependencies (The Right Way)

Simply updating the CLI isn't enough. You must ensure all @aws-cdk packages in your project match the CLI version.

Option 1: Using npm-check-updates (Recommended)

Manually editing versions in package.json is prone to human error. The best way to handle this is using the npm-check-updates (ncu) tool.

1. Install the tool (if you haven't already):

npm install -g npm-check-updates

2. Check for upgrades: Run this command in your project root to see which packages are outdated:

ncu

3. Update package.json: This command updates the version numbers in your file but doesn't install them yet:

ncu -u

4. Install the new versions:

npm install

Option 2: Manual Update

If you prefer doing it manually or don't want to install extra tools, you can force an install of the latest version for the core library:

npm install aws-cdk-lib@latest

If you are using CDK v1 (legacy) or separate construct libraries, you may need to update them individually, which is why Option 1 is generally faster.

Fixing Version Mismatch Errors

This is the most common issue developers face. You might see an error stating that the CDK CLI version is incompatible with the library version.

This happens because CDK requires the CLI and the Construct Library to be on the same major version (and ideally the exact same minor version).

The Fix:

1. Delete package-lock.json and node_modules: Sometimes cached dependencies cause the conflict to persist. You might want to review how to remove directory in linux commands to ensure you do this cleanly without leaving residual files.

rm -rf node_modules package-lock.json

2. Re-install dependencies:

npm install

3. Use npx for commands: Instead of relying on your global cdk command (which might be newer/older than your project), use npx to use the exact version installed in your project:

npx cdk deploy

Using npx ensures that you are always using the CDK binary that belongs to the current project, effectively eliminating version mismatch errors.

Handling Environment Variables During Updates

Sometimes, updates to the CDK introduce changes in how context or environment variables are handled. If your deployment relies on specific keys, ensure they are correctly loaded.

For a deeper dive into managing these configurations, you might want to check how to use environment variables effectively in your development workflow. This ensures that your updated stack still communicates correctly with other services.

Updating Python CDK Projects

If you are using Python instead of TypeScript, the process involves pip.

1. Update the CLI (This is still a Node.js tool, so you need npm):

npm install -g aws-cdk@latest

2. Update Python Dependencies: Open your requirements.txt file. You won't find a direct update all command like npm. You usually need to pin the version:

aws-cdk-lib==2.110.0
constructs>=10.0.0,<11.0.0

3. Install the new requirements:

pip install -r requirements.txt --upgrade

Testing Your Update Safely

After upgrading your CLI and libraries, never deploy directly to production. The logic of Infrastructure as Code means a small version change could alter resource definitions (like logical IDs) and trigger replacements you didn't intend.

Always synthesize your template first:

cdk synth

Then, deploy to a non-production environment. Understanding the differences between development staging and production environments is key here; you should validate that the update didn't break any existing integration before pushing changes to your live infrastructure.