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Module 33: Migration & Modernization

Migration & modernization is not just a technical upgrade — it is a functional, data, and code transformation.
ABAP developers play a key role in making custom code S/4HANA-ready.

1. ECC to S/4HANA Migration​

1.1 What Changes in S/4HANA?​

Key changes:

  • Simplified data models
  • Removal of aggregates & indices
  • CDS as primary data model
  • HANA-only database
  • Stricter syntax & checks
Core Reality

Custom code is the biggest risk in S/4HANA migration.

1.2 Migration Approaches​

ApproachDescription
System ConversionECC → S/4HANA
Landscape TransformationCentral finance, carve-out
New ImplementationGreenfield
Developer Impact

System conversion has the highest ABAP adaptation effort.

2. Support Package (SP) Adjustments​

What Are SP Adjustments?​

SP adjustments handle conflicts between:

  • SAP standard changes
  • Customer enhancements & modifications

Occurs during:

  • SP upgrades
  • S/4 upgrades

Tools Involved​

  • SPAU – ABAP Dictionary & Repository
  • SPAU_ENH – Enhancements
  • SPDD – Dictionary objects
Rule

Never blindly reset customer changes during SPAU/SPDD.

3. Custom Code Adaptation (Very Important)​

3.1 Why Custom Code Breaks​

  • Obsolete tables removed
  • Direct DB access invalid
  • Old Open SQL syntax
  • Unsupported statements
  • Hard-coded logic
Example

VBUP, VBUK replaced by CDS views.

3.2 Simplification Item Catalog​

SAP provides:

  • Simplification Item List
  • Notes explaining required changes
First Step

Always check Simplification Item Catalog before fixing code.

3.3 Custom Code Adaptation Tools​

ToolPurpose
SPAMSupport package management
SUMUpgrade execution
SNOTESAP Notes
ATCCustom code checks
CVICustomer/Vendor integration

3.4 ATC with S/4HANA Checks​

ATC → S/4HANA Readiness

Checks:

  • Obsolete APIs

  • Performance issues

  • Syntax incompatibilities

Mandatory Step

All custom code must be ATC clean before go-live.

4. SPAM / SUM Basics​

4.1 SPAM (Support Package Manager)​

SPAM:

  • Applies SAP support packages
  • Manages add-ons
  • Tracks SP levels
Usage

Used for maintenance, not full upgrades.

4.2 SUM (Software Update Manager)​

SUM:

  • Executes technical upgrade
  • Handles Unicode & S/4 conversion
  • Manages downtime
Developer Rule

During SUM:

  • No transports
  • Freeze development
  • Support testing only

5. Migration Phases (Developer View)​

Prepare → Explore → Realize → Deploy

Developer responsibilities:

  • Fix custom code
  • Remove obsolete access
  • Replace logic with CDS
  • Validate performance

6. Common Migration Pitfalls​

Avoid These
  • Skipping ATC checks
  • Ignoring simplification items
  • Using obsolete tables
  • Manual DB access
  • Underestimating testing effort

7. Interview-Grade Explanation​

Q: What is your role as an ABAP developer in ECC → S/4HANA migration?

Answer:

I analyze custom code using ATC and simplification items, adapt obsolete or incompatible logic, refactor code using CDS and modern Open SQL, support SP adjustments, and ensure all developments are S/4HANA compliant before go-live.

This Answer Works

Demonstrates hands-on migration experience.

8. Summary​

  • S/4HANA migration impacts custom code most
  • SP adjustments handle conflicts
  • ATC is mandatory for readiness
  • SPAM manages support packages
  • SUM handles upgrades
  • Modernization goes beyond syntax fixes

9. Practice Exercises​

  • Run ATC S/4 readiness checks
  • Fix an obsolete table access
  • Replace SELECT logic with CDS
  • Perform SPAU/SPDD adjustment
  • Review simplification item impact

10. What's Next?​

➡️ Module 34: ABAP Interview Preparation

Learning Tip

S/4HANA migration is where legacy developers fail and modern developers shine.