Linkerd Edge Release Roundup: September 2025

Welcome to the September 2025 Edge Release Roundup post, where we dive into the most recent edge releases to help keep everyone up to date on the latest and greatest! This post covers edge releases from August 2025.

How to give feedback

Edge releases are a snapshot of our current development work on main; by definition, they always have the most recent features but they may have incomplete features, features that end up getting rolled back later, or (like all software) even bugs. That said, edge releases are intended for production use, and go through a rigorous set of automated and manual tests before being released. Once released, we also document whether the release is recommended for broad use – and when needed, we go back and update the recommendations.

We would be delighted to hear how these releases work out for you! You can open a GitHub issue or discussion, join us on Slack, or visit the Buoyant Linkerd Forum – all are great ways to reach us.

Recommendations and breaking changes

All the August edge releases (edge-25.8.1 through edge-25.8.5) are recommended for everyone, so if you’re running an older edge release, now is a great time to upgrade! This goes double if you’re running edge-25.6.3 or higher and you’re using native sidecars – there’s a fix in edge-25.8.1 that you’ll definitely want.

As always, we have a couple of breaking changes to note:

• As of edge-25.8.3, the policy controller is included in the Linkerd controller image, and we no longer ship a separate policy-controller image. This should cut down on some image pull traffic, and it means that the policyController.image Helm value is no longer used.

• As of edge-25.8.2, we configure routing using the iptables-nft command by default, rather than with the older iptables-legacy. If your nodes don’t support iptables-nft, you can revert to using iptables-legacy by setting the iptablesMode value:

  • If you’re using the init container, set proxyInit.iptablesMode: legacy in the linkerd2-control-plane chart.

  • If you’re using Linkerd CNI, set iptablesMode: legacy in the linkerd2-cni chart.

• Finally, in edge-25.8.1, we dropped support for ARMv7 (the 32-bit architecture that powered things like the Raspberry Pi 2 and the Beaglebone Black). As far as we know, no one is using Linkerd on that architecture – if you are, please let us know!

One other interesting change is that in edge-25.8.4, the proxy switches to preferring the post-quantum key exchange algorithm X25519MLKEM768. This shouldn’t be a breaking change since we haven’t removed support for other algorithms.

The releases

As always, each edge release includes many dependency updates which we won’t list here. You can find them in the full release notes for each release.

edge-25.8.5 (August 27, 2025)

This release adds timeout and gateway error metrics to linkerd multicluster check, to better validate multicluster functionality.

edge-25.8.4 (August 22, 2025)

This release supports setting proxy.securityContext and the linkerd-proxy container, and the network-validator container, respectively. It also switches the proxy to prefer post-quantum key exchange algorithm X25519MLKEM768.

edge-25.8.3 (August 14, 2025)

This release eliminates the separate policy-controller image, instead including the policy controller in the main controller image. This means that the policyController.image Helm value is now ignored. It also adds a new rustls_info metric to make visible which cryptographic provider and algorithms are in use.

edge-25.8.2 (August 07, 2025)

This release switches the default command for programming the routing table from iptables-legacy to iptables-nft.

edge-25.8.1 (August 01, 2025)

This release fixes an issue (#14289) introduced in edge-25.6.3 where native-sidecar proxies would land in an error state after the main container exited. It also correctly sets app.kubernetes.io/version label to list linkerd/cli instead of linkerd/helm when installing a Linkerd extension using the CLI, and it removes support for ARMv7, notably including 32-bit Raspberry Pi platforms.

Installing the latest edge release

Installing the latest edge release needs just a single command.

curl --proto '=https' --tlsv1.2 -sSfL https://run.linkerd.io/install-edge | sh

You can also install edge releases with Helm.

Linkerd is for everyone

Linkerd is a graduated project of the Cloud Native Computing Foundation. Linkerd is committed to open governance. If you have feature requests, questions, or comments, we’d love to have you join our rapidly growing community! Linkerd is hosted on GitHub, and we have a thriving community on Slack, Twitter, and in mailing lists. Come and join the fun!

Linkerd generally does new edge releases weekly; watch this space to keep up-to-date. Feedback on this blog series is welcome! Just ping @flynn on the Linkerd Slack.