Deploy the new version in a separate App Engine application within the same project and use the App Engine library to proxy 2% of the requests to the new version.

Use the --splits option during deployment to allocate 98% of traffic to the current version and 2% to the new version within the same application.

Rewrite the existing deployment and utilize the --migrate option for deploying the new version.

Set up a new App Engine application in the same project and configure the network load balancer to direct 2% of traffic to the new application.