Buildkite Agent v4 is here

Buildkite Agent v4 is here. It's the first major version of the agent since v3 arrived in 2018, and it's now the stable release: installations and upgrades that follow the latest or stable channels now receive v4.

v4 clears out functionality deprecated over those eight years and makes current, supported behaviour the default, giving the agent a cleaner baseline for what we build next. New capabilities have continued shipping in v3, so for most setups the move changes nothing about how you use the agent.

The v3 → v4 upgrade guide covers every breaking change and how to migrate. The v4.0.0 release notes list what shipped. We announced the 1 September date in July.

What happens now

• Following latest or stable? Your next install or upgrade uses v4. Check the upgrade guide first if you haven't already.
• Pinned to a version? Nothing changes until you update the pin.
• Need more time? Stay on v3 by switching to the oldstable channel or setting the agent version to 3. v3 continues to receive critical security and reliability fixes, and we'll announce an end-of-support date with plenty of notice.

Hosted agents

We've started moving hosted agent organizations to v4 and will continue over the coming days. There's nothing for you to configure, and your agent version will update automatically when your organization moves.

Hosted agents run the same agent, so the upgrade guide applies to your pipelines too. Most setups need no changes, but it's worth a read if your pipelines use plugins or hooks.

If you experience any issues, contact support@buildkite.com or your account team.