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Author's profile photo Boris Rubarth

System Conversion to SAP S/4HANA: SUM is the tool

This blog discusses the technical aspects of Software Update Manager (SUM) for a
System Conversion: the transition of an existing SAP ECC system to SAP S/4HANA.

Readers should be familiar with the transition paths to SAP S/4HANA, like described in

Recording on system conversion at SAP TechEd 2022:

Recording on system conversion at SAP TechEd 2021:

Recordings on system conversion at SAP TechEd 2020:


System Conversion: SUM 2.0 is the tool for the transition to SAP S/4HANA on premise

  • System Conversion transitions an existing SAP ECC system to SAP S/4HANA (on premise)
  • Software Update Manager (SUM) is the tool for this transition

System Conversion: three tasks for SUM to enable Simplification of SAP S/4HANA

  • Software Update: Provide new applications & new tables (as part of the new data model) by providing new software components (like S4CORE) & updating existing software components
  • Database Migration (if source system is based on non-HANA database): migrate existing database content to SAP HANA database (using Database Migration Option DMO of SUM)
  • Data Conversion: conversion of table content to new data model

The data conversion is partly triggered by the SUM, partly an activity after the SUM run (for FIN and ML data: IMG activities).


  • Maintenance Planner has to be used beforehand to check the system and to provide the stack.xml for the SUM (as well as to provide the required software archives)
  • Simplification Item checks have to be executed beforehand, and all issues have to be solved, as the SUM will execute the same checks, and will stop in case of open issues
  • SAP Readiness Check is technically not required before starting the SUM – nevertheless it is highly recommended
  • SAP ECC 6.0 (with or without enhancement packages) is required as source release version
  • Source system has to be Unicode, and an ABAP single stack.

One-step or two: depends on Unicode (UC)

  • General rule:
    • If the source system is already on UC, the transition is a one-step procedure
    • If the source system is not yet on UC, the transition is a two-step procedure
  • Exception
    • For SAP R/3 4.7 and SAP ECC 5.0 Unicode systems: these releases do not include the Customer-Vendor-integration (with Business Partners) that is required for SAP S/4HANA, so a two-step approach is required
  • 😕 Yes, in general DMO may include the UC Conversion – but not for target NW 7.5:
    • NW 7.5 is only UC: no non-UC kernel (and no non-UC export load) available
  • Recommended path for non-UC source systems is discussed below

It is relevant for all target systems based on SAP NetWeaver 7.5 (also for systems part of SAP Business Suite 7 Innovations 2016, like SAP ECC 6.0 EHP 8) that the source system has to be already on Unicode.


One-Step conversion paths


Recommended path for two-step approach: goto 6.17

  • As discussed above, a two-step approach is required: for all non-UC systems and for R/3 4.7 & SAP ECC 5.0
  • Recommendation:
    • first step to for SAP ECC 6.0 EHP 7 (6.17) with SUM
    • second step later then with SUM (w/ DMO) to SAP S/4HANA
  • Alternative for SAP ECC 6.0 EHP 0…7 on anyDB:
    • You may only do the Unicode Conversion without update & migration (stay on software level)
    • Benefit: no change of business processes, so project effort may be reduce
  • Discussion:
    • Targeting EHP8 not possible, because it is based on 7.50 => requires UC source system


Best regards, Boris Rubarth

Product Manager Software Update Manager, SAP SE

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      Author's profile photo Former Member
      Former Member

      Excellent post Boris Rubarth...this makes me very clear now on system conversion to SAP S/4HANA.

      Author's profile photo Andy Silvey
      Andy Silvey

      Hi Boris,

      long time no see, nice blog.

      Hope you are doing fine,


      Author's profile photo Sergio Guerrero
      Sergio Guerrero

      great post... all this is now more clear that is also presented on the S/4HANA implementation openSAP course. thank you for sharing

      Author's profile photo Ning Tong
      Ning Tong

      Hi Brois,

      For customer starting from 4.6c on anyDB, it is better to do the following steps, right?

      1. CU&UC to ERP 6.0 EHP 7

      2. SUM/DMO to S/4HANA?


      Ning Tong

      Author's profile photo Shubham Srivastava
      Shubham Srivastava

      very well explained...good document

      Author's profile photo Former Member
      Former Member

      Well explained, Thanks a lot Boris!

      Author's profile photo Ralf Haida
      Ralf Haida

      Where I get more details on post processing / Data conversion ?

      Author's profile photo Ambarish Satarkar
      Ambarish Satarkar

      Hi Boris,

      I really like the way you explain things! This blog makes understanding of system conversion to s/4hana very simple. Everyone knows practically converting traditional ERP system to s/4hana system is not so simple. 😛

      I really appreciate simplicity you have kept in explaining complex things from the beginning.

      Thanks again 🙂


      Author's profile photo Antonio Vacas Zambrano
      Antonio Vacas Zambrano

      Hi Boris

      I'm suprised that if I want to convert my ERP to S4HANA with System Move I cannot have HANA as a source database. What's the reason? conversion + system move is an advantage if we want to move to a Hyperscaler but if you are already in HANA you cannot do it


      Kind regards, Antonio

      Author's profile photo Boris Rubarth
      Boris Rubarth
      Blog Post Author

      Hi Antonio,

      DMO does only allow heterogenous migrations, same applies for "DMO with system move".

      Kind regards, Boris

      Author's profile photo Antonio Vacas Zambrano
      Antonio Vacas Zambrano

      Hi Boris

      So if I want to move to S4HANA using brownfield approach I cannot combine conversion and moving to another datacenter in the same process, is that right? We will need to migrate to a new datacenter / hyperscaler and then convert to S4HANA or convert to S4HANA and later move to another datacenter/hyperscaler

      Is there any plan to enable DMO with System Move using HANA as a source? It's strange to loose a migration option for being already in HANA is a handicap for many customers like my company

      Kind regards, Antonio

      Author's profile photo Boris Rubarth
      Boris Rubarth
      Blog Post Author

      Hi Antonio,

      I would not state that you loose a migration option, but I see your point. As far as I know, there is currently no plan to enable the homogenous migration case with SUM. I am not aware of a one-step procedure in this case. If I find a proposal other that the two-steps you listed, I will let you know.

      Kind regards, Boris

      Author's profile photo Antonio Vacas Zambrano
      Antonio Vacas Zambrano

      Many thanks.


      Hope we will meet you next Teched if we have luck with the COVID situation

      Author's profile photo Rajeshwar Kothapalli
      Rajeshwar Kothapalli

      I agree with Antonio , we have a similar business need where it would have been nice to perform homogeneous brownfield system conversion  with system move & inline SID conversion , for example going from BSoH-ECC SID:EC1 with hostname (distributed hostnames: sapec1* , onprem/hyperscaler)  to S4HANA-SID:S41 (distributed hostnames:saps41* , onprem/hyperscaler)


      Wanted to do a mention to express there are more similar needs and bring to SAP's attention.

      Author's profile photo K JESU BALAN