If you upgrade your TFS installation to a newer version, a new version of the build agent is available as well.
To upgrade your agents, you have 2 options:
- If a new major version of the agent is released, you’ll have to manually delete the old agent and install a new agent.
- If a new minor version of the agent is released, the existing agent is upgraded automatically when it runs a task that requires a newer version of the agent.
- If you want to trigger the update manually, you can go to the Agent Pool hub, right click on a Queue and click on Update All Agents.
More information at https://docs.microsoft.com/nl-nl/vsts/build-release/concepts/agents/agents#agent-version-and-upgrades