When you create a Lambda function, there is only one version - the $LATEST version.
When you release version, AWS Lambda in $LATEST creating a snapshot copy of the Lambda function code (and configuration) versions. The released version is immutable . In other words, you can not change the code or configuration information . ARN new version has a unique version number suffixes, as shown below.
Lambda function of each version has
a unique Amazon Resource Name (ARN). Once published version, you can not change.
AWS Lambda also supports the creation of your Lambda function version of each alias Alias . Conceptually, AWS Lambda alias alias is a pointer to a specific version of the Lambda function pointer. It is also similar to the resource Lambda functions, each alias has a unique ARN. Each alias that points to the function to retain a version of ARN. Aliases can only point to a function version, but can not point to other aliases. With different versions, you can modify the alias. You can update the alias to point to a different version of the function.
The use of aliases, from the Lambda function version of the map and the event source abstraction new version of Lambda functions to improve the process of production.
Further: CodeBuild in buildspecOverride: optional string. Construction of the project as defined in the build specification statement covering this building project. If this value is set, it may be generated inline specification defines, may be directed with respect to the built- CODEBUILD_SRC_DIR path environment variable value alternatively build specification file. Select Use a buildspec file (using the build specification file) for use in the source root directory buildspec.yml .