How to create a REST API with serverless

Link to chapter — How to create a REST API with serverless | Serverless Stack

How to create a REST API with serverless in this chapter when trying to execute getting error saying:

❌  SSTBootstrap failed: Resource handler returned message: "The runtime parameter of nodejs14.x is no longer supported for creating or updating AWS Lambda functions. We recommend you use a supported runtime while creating or updating functions. 

Any solutions available? Tried to set runtime for lambda but not working