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AWS lambda documentation change

Service: lambda · 2025-08-28 · Documentation low

File: lambda/latest/dg/configuration-versions.md

Summary

Expanded documentation to list configuration changes that trigger Lambda version publication and clarify version immutability

Security assessment

This is a functional documentation update about versioning mechanics. While versioning supports auditability (a security-adjacent concern), there is no direct evidence of a security issue being addressed.

Diff

diff --git a/lambda/latest/dg/configuration-versions.md b/lambda/latest/dg/configuration-versions.md
index 15d85e730..8e98501cf 100644
--- a//lambda/latest/dg/configuration-versions.md
+++ b//lambda/latest/dg/configuration-versions.md
@@ -106,0 +107,2 @@ If you decide not to publish function versions, you can invoke the function usin
+The qualified ARN for each Lambda function version is unique. After you publish a version, you can't change the ARN or the function code.
+
@@ -109 +111,42 @@ Lambda publishes a new function version only if the code has never been publishe
-The qualified ARN for each Lambda function version is unique. After you publish a version, you can't change the ARN or the function code.
+When you publish a version, Lambda creates an immutable snapshot of your function's code and configuration. Not all configuration changes trigger the publication of a new version. The following configuration changes qualify a function for version publication:
+
+  * Function code
+
+  * Environment variables
+
+  * Runtime
+
+  * Handler
+
+  * Layers
+
+  * Memory size
+
+  * Timeout
+
+  * VPC configuration
+
+  * Dead Letter Queue (DLQ) configuration
+
+  * IAM role
+
+  * Description
+
+  * Architecture (x86_64 or arm64)
+
+  * Ephemeral storage size
+
+  * Package type
+
+  * Logging configuration
+
+  * File system configuration
+
+  * SnapStart
+
+  * Tracing configuration
+
+
+
+
+Operational settings such as [reserved concurrency](./configuration-concurrency.html) don't trigger the publication of a new version when changed.