awsPractitioner

Automate AWS Lambda Runtime Upgrades with AWS Transform Custom

5 min read AWS DevOps BlogMar 2, 2026Reviewed for accuracy

Practitioner — Hands-on experience recommended

In the fast-paced world of cloud computing, keeping your AWS Lambda functions up to date can be a daunting task, especially with the deprecation of runtimes like Python 3.8. AWS Transform custom exists to alleviate this burden by automating the upgrade process, ensuring that your functions run on supported and secure runtimes without the need for specialized automation expertise.

AWS Transform custom works by leveraging an intelligent AI agent that learns your organization's specific code transformations. It automates the migration of Lambda functions from deprecated runtimes to modern versions. For instance, you can seamlessly upgrade from Python 3.8 to Python 3.13. To get started, ensure you have the AWS Transform CLI installed and configured, along with proper IAM permissions. Use the -t flag to trust all tool executions without confirmation, streamlining the process but also introducing some risk, as it allows the agent to run shell commands automatically.

In production, you need to be aware of the potential pitfalls. The -t flag can be convenient for quick walkthroughs but may lead to unintended consequences if not handled carefully. Additionally, ensure that your development environment is properly set up with Git and the uv package manager for Python environments. Keep in mind that deprecated runtimes like Python 3.8, Node.js 14, and Java 8 are on the chopping block, making timely upgrades essential for maintaining application performance and security.

Key takeaways

→Automate migration from deprecated runtimes like Python 3.8 to Python 3.13 using AWS Transform custom.
→Use the `-t` flag to trust all tool executions, but be cautious of the risks involved.
→Ensure proper IAM permissions and AWS Transform CLI configuration before starting the upgrade process.
→Leverage the intelligent AI agent to learn organization-specific code transformations for consistent upgrades.
→Stay updated on deprecated runtimes to avoid security vulnerabilities and maintain performance.

Why it matters

In production, automating runtime upgrades can save significant time and reduce the risk of human error, ensuring your applications remain secure and performant. This is crucial as AWS deprecates older runtimes, which can lead to vulnerabilities if not addressed promptly.

Code examples

Bash

1git clone https://github.com/aws-samples/sam-python-crud-sample.git
2cd sam-python-crud-sample
3uv venv --python 3.8 # uv will automatically download Python 3.8 if not already installed
4source .venv/bin/activate
5uv pip install -r requirements.txt
6uv pip install -r requirements_dev.txt
7uv pip install "moto[dynamodb]<3"
8python -m pytest tests/ -v -o "addopts="

Bash

atx -t

When NOT to use this

The official docs don't call out specific anti-patterns here. Use your judgment based on your scale and requirements.

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Automate AWS Lambda Runtime Upgrades with AWS Transform Custom

Key takeaways

Why it matters

Code examples

When NOT to use this

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