Lesson 2 of 5
The N+1 landscape
9 min
The usual answer to dual maintenance is an N+1 landscape. "N" is the current release, the landscape that supports production today. "N+1" is the next release, the project landscape where the new system is built. Production stays attached to N until cutover. The N+1 track runs beside it with its own development and test systems, and changes flow from N to N+1 through retrofit, never the other way.
| N: maintenance track | N+1: project track | |
|---|---|---|
| Release | SAP ECC 6.0 EHP 8 | SAP S/4HANA 2025 (converted) |
| Development | ED1 | CMD |
| Quality | EQ1 | CMQ (client 100 for testing) |
| Production | EP1 (live) | CMP after cutover |
| Allowed changes | Fixes, legal changes, approved small changes | Project scope, plus retrofits from N |
| Change tool | Existing ECC change process | Features in SAP Cloud ALM |
How the N+1 track is built in a conversion
SAP's conversion guidance follows a sequence: convert a sandbox made from a production copy first to learn, then convert development, then quality, then rehearse with a production copy, and finally convert production. Each step needs the maintenance track to keep running on the old release. At Contoso, Sam created CMD from a copy of ED1 and converted it; ED1 itself stayed on ECC for maintenance. CMQ followed the same way from EQ1.
- SandboxCopy EP1, convert; learn the technical steps and custom code impact
- DevelopmentCopy ED1 to CMD, convert; ED1 continues as maintenance development
- QualityCopy EQ1 to CMQ, convert; EQ1 continues as maintenance test
- RehearsalCopy EP1, convert in rehearsal; measure downtime
- ProductionConvert EP1 at cutover; N track retired
Transport routes
The two tracks need separate transport routes so that nothing moves between them by accident. ED1 transports go to EQ1 and EP1. CMD transports go to CMQ and, at cutover, become part of the production build. A transport from ED1 must never be imported straight into CMD or CMQ: the objects there have been converted and adapted, and an old version would overwrite them. Retrofit is a controlled step, not an import.
Clients, users and data in N+1
An N+1 track is more than system copies. Developers and testers need users in both tracks, and it must always be obvious which track they are in, so Sam gives the S/4HANA systems a distinct logon banner and color scheme. Test data in CMQ will age as the project runs; plan refreshes carefully, because a refresh of a project system from ECC production would wipe converted work. The usual answer is to refresh test data in CMQ through migration loads or data tools, not through system copies, once the track is built.
Cost and alternatives
An N+1 track roughly doubles the development and test infrastructure for the length of the project. Smaller programs sometimes accept a longer freeze instead, or keep only an emergency repair copy of production. The trade-off is time versus money: the longer the project, the more an N+1 track pays for itself in flexibility.
What would you do?
Kenji needs an ECC user-exit fix in the S/4HANA project system quickly. He asks Sam to add ED1's transport to the CMQ import queue "just this once". What should Sam do?
- N is the maintenance landscape supporting production; N+1 is the project landscape.
- In a conversion, project systems are copies of ECC systems converted step by step; each copy date starts divergence.
- Keep transport routes separate; never import N transports directly into N+1.
- An N+1 track costs infrastructure; weigh it against project length and change volume.
Check your understanding · not graded
Lesson check
1. In an N+1 landscape, what does N+1 refer to?
2. Why must ECC transports not be imported directly into S/4HANA project systems?
3. Which SAP conversion step comes first?