When Control Tower deploys Concourse, it now adds a pipeline to the new Concourse called control-tower-self-update. This pipeline continuously monitors our Github repo for new releases and updates Concourse in place whenever a new version of Control Tower comes out.
This pipeline is paused by default, so just unpause it in the UI to enable the feature.
Patch releases of control-tower are compiled, tested and released automatically whenever a new stemcell or component release appears on bosh.io.
To upgrade your Concourse, grab the latest release and run control-tower deploy --iaas [AWS|GCP] <your-project-name> again.