AWS Lambda: Ruby 3.4 (ruby3.4) deprecation

After deprecation (31 Mar 2028), AWS may no longer apply security patches or updates to the runtime, and functions using it are no longer eligible for technical support. Functions can still be invoked indefinitely, but may experience degraded performance or other issues, such as a certificate expiry, that can cause them to stop working properly.

• Deprecation: the Lambda console no longer creates or updates functions with this runtime. The AWS CLI, AWS SAM, and CloudFormation still do.
• Block function create (date: 30 Apr 2028, at least 30 days after deprecation): Lambda begins blocking creation of new functions.
• Block function update (date: 31 May 2028, at least 60 days after deprecation): Lambda begins blocking the update of code and configuration for existing functions.
• Lambda does not block creates or updates before the dates in its runtime tables. Forecast dates are subject to change.

1. List the affected function versions with Trusted Advisor or with Retrieve data about Lambda Event Functions that use a deprecated runtime.
2. Test each function with the new runtime before applying changes in production environments.
3. Update the function to a newer supported runtime. This is possible at any time after the runtime is deprecated. In the Block function update phase (date: 31 May 2028), Lambda begins blocking the update of code and configuration for existing functions, but the function configuration can still be upgraded to a supported runtime. See Managing AWS Lambda runtime upgrades.
4. Use function versions and aliases to enable deployment with rollback. After function updates are blocked, reverting to the deprecated runtime is not possible.