Developers using AWS Lambda with PHP 8.4 often hit a wall when trying to enable the IMAP extension. The popular Bref framework provides many PHP extensions as pre-built layers, but IMAP isn't available for PHP 8.4 due to complex system dependencies like c-client and Kerberos libraries that must be compiled for Lambda's Amazon Linux 2 environment.

The solution involves Docker multi-stage builds using Bref's dedicated compilation image. You compile the IMAP extension in a build stage, then copy the compiled `.so` file and its dependencies to the final runtime image. This method gives full control over the environment and ensures compatibility with Lambda's specific operating system requirements.

Deployment pushes the custom container images to AWS ECR, where Lambda functions reference them directly. The Serverless Framework automates building and deploying these images for different function types: web, CLI, and queue workers. This approach works for any missing PHP extension, keeping images small and builds reproducible.