After updating to use CDK v2 I see this message for each file upload in the build process

"cdk bootstrap" to version 9 if your organization's policies prevent a successful upload or to get rid of this message)

Is there a recommended way of bootstrapping since this was done originally by the SST framework?

Ross, I just went with

cdk bootstrap aws:<account-to-be-bootstrapped-again>:<region>

We should automatically update the bootstrapped stack. Opened an issue to track this https://github.com/serverless-stack/serverless-stack/issues/1391