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ADR 056: OpenShift Support Window 4.20–4.22

Status

Accepted

Ratified 2026-09-12 by repository owner (tosin2013). Supersedes ADR-002.

Context

ADR-002 (Accepted, 2025-11-07) certifies OpenShift 4.18, 4.19, and 4.20 as Tier 1, with Kubernetes 1.25+ as best-effort. That window no longer matches Red Hat’s OpenShift lifecycle as of 2026-09-12.

What changed

OpenShift Kubernetes (release notes) GA Phase on 2026-09-12
4.18 1.31 2025-02-25 EUS Term 1. Maintenance ended 2026-08-25 (RHBA-2026:29706)
4.19 1.32 2025-06-17 Maintenance (ends ~2026-12-17). No EUS
4.20 1.33 2025-10-21 Maintenance. EUS floor
4.21 1.34 2026-02-03 (RHBA-2026:1481) Maintenance (Full Support ended ~90 days after 4.22 GA)
4.22 1.35 2026-06-09 (RHEA-2026:0449) Full Support. EUS
4.23 — Not GA (CI/nightlies only) Do not certify

This repository’s own April 2026 matrix already said operator support for 4.18 would be dropped when 4.22 shipped. Both events have happened.

Catalog metadata already claims com.redhat.openshift.versions: v4.19-v4.22 while CSV prose and ADR-002 still describe 4.18–4.20. That disagreement is evidence for a supersede, not permission to silently rewrite ADR-002.

Policy: OpenShift Container Platform Life Cycle — about a four-month minor cadence, at least four minors supported at once, even minors are EUS, maintenance ends 18 months after GA.

This operator is community-distributed. Aligning the certified window to Red Hat’s calendar does not inherit Red Hat Operator life-cycle classifications.

Tree today

go.mod still pins k8s.io/api v0.31.10 (4.18-era APIs). Installability on a newer cluster is not the same as a client-library bump. This ADR does not authorize a k8s.io, ENVTEST, or Operator SDK upgrade.

Decision

We will certify a rolling three-minor OpenShift window whose high end is the current EUS GA:

Tier 1 — Certified

  • OpenShift 4.20, 4.21, and 4.22
  • OLM annotation: com.redhat.openshift.versions: v4.20-v4.22
  • Kubernetes mapping: 1.33 / 1.34 / 1.35
  • Testing, bug fixes, and support claims apply only to this window once this ADR is Accepted

Drop from Tier 1

  • OpenShift 4.18 — drop from certified support. Remaining release-4.18 history is frozen for new certified claims.

Best-effort (not certified)

  • OpenShift 4.19 — still in Red Hat maintenance until ~2026-12-17, no EUS. No dedicated CI obligation.
  • Upstream Kubernetes: best-effort on versions that correspond to the certified OpenShift minors (1.33–1.35), not the ADR-002 “1.25+” floor.

Out of the window

  • OpenShift 4.23 and later — not certified until GA plus an assigned, tested follow-on ADR or issue.

What this does not decide

  • Client library or Operator SDK upgrades (k8s.io may remain v0.31.x until a later authorized issue).
  • Creating release-4.22 or reusing issue #16 (v1.0.9 / release-4.20 bundle) as the 4.22 vehicle.
  • OperatorHub republish, CSV marketing text, or README install tags (follow-on after ratification).
  • ADR-006’s historical 4.18-first phased roadmap and ADR-046’s 4.18/4.19/4.20 bundle table — named as related drift; not rewritten here.

When 4.24 (next EUS) is GA, the expected roll is 4.22 / 4.23 / 4.24 via another Proposed ADR, not an in-place edit of this file.

Consequences

Positive

  • Claims can match Red Hat’s current Full Support / Maintenance set instead of an EUS-only 4.18 floor.
  • EUS-to-EUS cluster path 4.20 → 4.22 stays in the certified window.
  • OLM range can be narrowed from the current v4.19-v4.22 annotation to v4.20-v4.22 after ratification.

Negative

  • Users remaining on 4.18 leave certified support while their clusters may still be on EUS Term 1.
  • Three OpenShift versions still need CI if we honour “certified.”
  • ADR-046’s per-stream bundle table and origin/release-4.18 become stale (discovery for a later issue).
  • Catalog already advertised 4.19–4.22; dropping 4.19 from certified is a claim change, not only a 4.18 drop.

Neutral

  • Lowest-common-denominator Kubernetes APIs in the operator binary may still be 1.31 until a separate bump.
  • Odd-numbered 4.21 stays in the window as the middle minor, not as its own “stream” product.

Implementation Notes

  1. Ratification: human sets this ADR to Accepted and ADR-002 to Superseded by ADR-056.
  2. Then issue #45 may reconcile GitHub milestones v1.0.9 / v1.0.10 with this window (do not bulk-move issues).
  3. Follow-on (not this ADR): CSV description, README, docs/OPENSHIFT_SUPPORT_MATRIX_AND_STRATEGY.md, OLM annotation v4.20-v4.22.

References

  • ADR-002: Platform Version Support Strategy (to be superseded)
  • ADR-006: Version Support Roadmap and Testing Strategy (4.18-first phases; related drift)
  • ADR-007: Distribution and Catalog Strategy
  • ADR-029: Platform Version Dependency Review Process
  • ADR-032: GitHub Actions CI Testing Against Kubernetes 1.31.10
  • ADR-046: Multi-Version Bundle Strategy and Upgrade Chain (4.18/4.19/4.20 table; related drift)
  • ADR-055: OperatorHub Submission Lessons Learned (olm.skipRange)

Revision History

Date Author Description
2026-09-12 Tosin Akinosho / agent under #44 Proposed window; does not ratify