By default, you can use either IMDSv1 or IMDSv2, or both. The instance metadata service distinguishes between IMDSv1 and IMDSv2 requests based on whether, for any given request, either the PUT or GET headers, which are unique to IMDSv2, are present in that request.

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/configuring-instance-metadata-service.html