Upgrading an IBM i release is less about clicking an install button and more about deciding whether the environment is ready for the next level.
Why this matters
Compatibility planning matters because applications, interfaces, and operational scripts may depend on behavior that changes across releases.
Core concepts
Inventory
Start by listing what the current environment depends on.
Test first
A non-production partition or test system should validate the upgrade path before production.
Compatibility checks
Each application and integration should be reviewed for release-specific risk.
Cutover discipline
A good upgrade plan includes timing, owners, validation, and rollback.
Practical example
Before a production upgrade, a team can clone the workload into a test environment, run the critical jobs, and document what must change before cutover.
Common mistakes
- Assuming the old release’s behavior will stay identical everywhere.
- Skipping application validation because the operating system upgrade looks routine.
- Treating rollback planning as optional.
Where this fits in the series
If you want the platform foundation first, read the pillar article, What Is AS400 (IBM i)? A Complete Beginner’s Guide.