2026 R2 Modern UI Migration Readiness Checklist

Step 1 - Inventory every customization

• Export the list of all customization projects (Customization Projects screen, SM204505) with their publish status.
• List every custom screen (custom ASPX pages and custom graphs) and who owns each business process it supports.
• List modified out-of-the-box screens (screens with layout or logic changes published on top).
• Collect custom reports, generic inquiries, dashboards, and pivot tables that users rely on daily.
• Note any screen where you no longer know why the customization exists. Those need a business review, not just a migration.

Step 2 - Identify Classic UI dependencies

• Open each custom screen and confirm whether it renders in Modern UI or falls back to Classic UI.
• Flag screens built with Classic UI ASPX layouts. These are the ones affected by XSLT removal.
• Check customized standard screens: a Classic-era layout customization can block the Modern UI version of the same screen.
• Ask your users which screens they open in Classic UI on purpose. Muscle memory hides risk.

Step 3 - Check your ISV and third-party solutions

• List every ISV solution installed in your instance and its version.
• Ask each vendor for their Modern UI / 2026 R2 compatibility statement in writing.
• Flag abandoned or out-of-support ISV products. These often become rebuild candidates.

Step 4 - Categorize by complexity

• Simple: layout tweaks, added fields, minor logic. Typically 1-3 days each to migrate.
• Medium: custom screens with business logic and events. Plan roughly a week each.
• Complex: custom modules, multi-screen flows, integrations. Plan 2-4 weeks each.
• Retire: screens that duplicate functionality Acumatica has since added natively. Don't pay to migrate what you can delete.

Step 5 - Verify your upgrade path

• Confirm your current Acumatica version and how many upgrades away 2026 R2 is for you.
• Check whether your customizations are published from source control or only exist in the production instance.
• Confirm you have a sandbox/dev instance that mirrors production for testing.

Step 6 - Run a pilot migration

• Pick one medium-complexity screen and migrate it in the sandbox first.
• Measure the actual effort against your estimate. Recalibrate the plan with real numbers.
• Have the screen's daily users test it. UI parity on paper is not workflow parity in practice.

Step 7 - Build the timeline backwards from 2026 R2

• Set your target completion at least one quarter before you plan to take 2026 R2.
• Sequence business-critical screens first, cosmetic ones last.
• Include UAT sign-off and a production deployment window in the plan, not just development time.

Step 8 - Plan training and rollout

• Modern UI changes navigation and layout. Budget a short orientation for daily users.
• Keep a rollback plan: unpublish path, database snapshot, and a freeze window for go-live.
• Document the migrated state so the next upgrade doesn't restart this exercise.