Helm v3.18.x compatibility issue with CircleCI Server

Problem

CircleCI Server installation or upgrade via helm upgrade fails unexpectedly after updating the Helm client to v3.18.x. The errors may vary depending on which regression you have encountered, but common symptoms include:

Failures pulling OCI-based chart dependencies
Template rendering errors such as incompatible types for comparison
helm lint rejecting JSON Schema $ref URLs that worked in v3.17.x

These failures are not caused by changes to CircleCI Server itself. Helm v3.18.0 introduced a series of upstream regressions that affected multiple charts across the ecosystem, not just CircleCI's.

Solutions

Solution 1 — Downgrade Helm to v3.17.x (immediate fix)

Install Helm v3.17.3 from the official releases page
Re-run your helm upgrade or helm install command
This is the fastest resolution if you need to unblock immediately

Solution 2 — Upgrade Helm to v3.19.0 or later (recommended)

Helm v3.18.1 addressed the OCI pull and registry login regressions but still contained known issues
v3.19.0 resolved the remaining v3.18 regressions including OCI chart pulls, helm lint JSON Schema $ref handling, and redirect registry failures
Helm v3.20.0 is the current stable release — upgrading to the latest stable is the preferred long-term path
See Helm releases for binaries and checksums

Confirm your Helm version:

helm version

Outcome

After switching to a supported Helm version (3.17.x or 3.19.0+), your helm upgrade should complete successfully. If failures persist after the version change, they are likely unrelated to this regression — open a support ticket with the full helm upgrade --debug output.

Additional Notes

Helm v3.18.0 introduced several distinct regressions simultaneously, which is why the symptom pattern varies. The relevant upstream issues are:

OCI media type rejection: helm/helm#30890
Template type comparison breakage (integer vs float): helm/helm#30908
OCI pull regression tracked in v3.19.0 release notes: helm/helm#31776

CircleCI Server is not uniquely affected — this impacted the broader Helm ecosystem. If you are running Helm v3.18.x and encountering unexpected failures with any chart, version-pinning is the first diagnostic step to rule this out.

Additional Resources