AEM 6.4 to 6.5 Migration: Compatibility and Release Validation.

Start with an inventory of the source installation and a declared target baseline. Record custom bundles, integrations, content packages, indexes and delivery configuration so regressions can be compared against a known starting point.

A bundle can resolve while a component still renders incorrectly or a workflow fails against migrated content. The upgrade assessment needs to include behavior that package installation alone cannot verify.

• List deprecated API references and third-party dependency constraints.
• Identify representative authoring journeys, integrations and content types.
• Separate existing defects from changes introduced by the upgrade.

Use a controlled test environment with representative content and the target application packages. Keep repository changes, code changes and delivery configuration identifiable so a failed request can be traced to the layer that changed.

For each custom feature, record the current behavior, compatibility finding, remediation and validation evidence. Review Maven dependency changes and OSGi resolution together, then test content access and rendering on the target baseline.

• Remediate deprecated APIs with behavior-focused tests.
• Review Oak query plans for representative repository reads.
• Exercise publication, cache invalidation and cached page delivery.

The proposed release keeps feature behavior stable while resolving compatibility gaps. This makes a failure easier to attribute than a release combining a runtime upgrade, content-model redesign and unrelated UI work.

Deferring features reduces variables but does not remove integration risk. A rollback decision must consider repository and content state as well as application packages; deploying old code is not a complete recovery plan.

For the next runtime assessment, distinguish this release from AEM 6.5 LTS compatibility and modernization.

Use a release checklist with expected behavior and retained results rather than claiming readiness from an installation log.

• Compare representative rendered pages and authoring actions against the source baseline.
• Check bundle resolution, service activation, query plans and application logs.
• Rehearse publication, integration failure behavior and recovery in a non-production environment.

A warm Dispatcher cache can conceal a Publish rendering regression after the upgrade. Validate a cold request, a warm hit and publication-driven invalidation separately. If repository state changed, prove recovery with a restore rehearsal instead of assuming an older application package is a rollback.

The useful deliverable is an explanation of what changed and why the remaining risk is acceptable. No measured production outcome or completed client rollout is asserted here.

These sources document product behavior. The design and validation approach above are engineering proposals, not claims made by the vendors.

• Adobe: upgrading AEM 6.5 code and customizations