Background

Minor releases (starting with MongoDB 8.2) support production quality for on-premise deployments, unlike the previous rapid releases which were Atlas-only. As a result, minor releases require the same level of compatibility test coverage as major releases.

The Server Release Policy defines a comprehensive Upgrade/Downgrade Paths matrix. Currently, compatibility test coverage for minor releases is not fully in place.

Goal

Ensure all upgrade/downgrade path combinations listed in the Server Release Policy matrix are covered by WiredTiger compatibility tests, including:

• Minor release ↔ adjacent minor release (e.g. 8.2 ↔ 8.1, 8.2 ↔ 8.3)
• Minor release ↔ adjacent major releases (e.g. 8.2 ↔ 8.0 and 8.2 ↔ 9.0)

At any given time there should be only 2 adjacent minor releases to support in terms of compatibility.

Proposed Change

• Audit existing compatibility tests against the full upgrade/downgrade matrix.
• Add missing test coverage for minor release series (treating them the same as major releases).
• Update version configurations to include minor release series going forward as new ones are introduced.

Context

This work is part of a broader effort to improve WiredTiger compatibility tests. See WT-17179 for details.