Can you estimate the S/4HANA Custom Code migration ?

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The Holiday Question

It was just one of these traditional friday mornings, you sat there enjoying a nice cup of coffee and the summer holiday was just around the corner. And then this harmless e-mail arrived from your project manager. He was just in the process of finalizing the first draft of the project plan for the company plans for the S/4HANA migration… and he just need your input on the task of migrating the Custom Code….. and he would love to have that estimate before you went for vacation. End of the day – it’s just an estimate 🙂 

So the question that came to my mind was “How complicated could that be? We have SAP standard tools for S/4HANA Readiness checks – I will just run that and have a nice foundation for the estimation”.

And that’s were the assumptions might collide a bit with your upcoming summer vacation. At least if you plan to enjoy the sunshine and stay outside for a bit. 

Why? Well in order to do a proper estimation, you need an overview of how you will be impacted. The S/4HANA simplification database contain references to more than 300 SAP Notes, and these 300 Notes consist of more than 300.000 Simplification items. And when you run the SAP S/4HANA Readiness Check you end up with a very very long list of issues found in your custom code, all relating to both Notes and simplification Items.

Can you use this Issue List for estimation – and how?

For example; if one of your custom reports has an S/4HANA Readiness issue referring to an SAP Note saying that your custom code uses elements not planned in the S/4 Roadmap, is this then a critical issue and how do I fix it? And how much time should I estimate for this? If your custom code is just referring to a data element in this discontinued SAP package, then it will be a small thing to fix. If, on the other hand, custom code uses a long list of classes in this SAP package, you have a more complex issue on your hands.  

How do you find this in the S/4HANA Readiness check? And how do you convert this into an estimate?

Tadaaa.. I will use my favorite tool, Excel. In wonderfully versatile tool, I will import the list and group the list on SAP Notes. But alas, I find myself cornered by a missing overview, missing details, free text references to SAP Notes…. and only the possibility to do estimation at SAP Note level. And that won’t work. This is too high level, because what you really need it to go one step deeper and estimate at simplification item level instead. 

And just to add insult to injury before the summer vacation, your project manager asked you to only include Custom Code related to 20 critical business processes. As he said: “There’s no need to spend time on Custom Code which we don’t plan to use in the new S/4HANA system…”   

S/4HANA Estimation Simplified

The Gekkobrain S/4HANA Estimation tool could help you with a more relaxing summer vacation. 

We have addressed this complex estimation task, and we offer a complete set of estimations all the way down to each individual simplification item. So if for example your custom code only refers to a few data elements that aren’t part of the S/4 Roadmap, we will know and tell you it’s a small task. On the other hand, Gekkobrain will also find the usage of those critical classes that will determine you need to refactor the custom code, and it  will provide you with an estimate for this more complex task. 

And how do Gekkobrain know how much time your developers need to refactor the code? Well, we estimate in T-shirt sizes at simplification item level and then offer the customer the possibility to map each T-shirt size into Best, Worst and Realistic time. So end of the day, we can offer you estimates from Custom Code Object level all the way up to a total estimate for the entire SAP system.

We offer to breakdown the estimates into:

  • An estimate per application/sub-application area
  • An estimate per development class
  • An estimate per SAP Note 
  • An estimate per Issue Type
  • An estimate with or without Usage (UPL/SCMON) information
  • An estimate per Logical Solution Component (see next section)   

All you need to get started, is to run the SAP standard S/4HANA Readiness Check and transfer the results to the Gekkobrain S/4HANA Estimation, which will instantly provide you with feedback on the estimate. You can of course finetune this to tailor the final estimates. And you can also slice and dice with the numbers based on the requirements, for example,  you can simulate how the estimate will be impacted if you take out individual dev. classes or Notes.  

Some Examples of S/4HANA Estimation in Gekkobrain

Estimate of resources needed to migrate code to S/4HANA by development class
Estimate by Issue Type

Logical Solution Components

Coming back to the request for the Project Manager regarding custom code related to selected Business Processes, this can also be achieved very simply in Gekkobrain S/4HANA Estimation. The tool uses what we call Logical Solution Components to group custom code and this grouping can be used for various purposes. 

One purpose could be to find on custom code related to selected business processes. And if you wonder: Why not just migrate everything? Well, because it’s monumental task in itself to migrate the Custom Code and migrating everything makes no sense. So, you need to minimize the scope by firstly disregarding unused Custom Code from the equation. Secondly you should narrow in on only the Custom Code you would need to support critical business processes in S/4HANA. Finally you should abandon old Custom Code on ECC, if it will be replaced by SAP standard functionality. Summing it up, you shouldn’t spend any time migrating the following code to S/4HANA:

  • Unused code
  • Code that’s replaced by standard functionality in SAP 

The Gekkobrain Logical Solution Components can be used to filter you code for you and reduce the scope. The custom code will be analyzed and grouped in various ways:

  • By Application area/sub application
  • Automatically based on Business Processes found in Gekkobrain Flows
  • Automatically based on Clustering (we use AI to find related Custom Code)
  • By manually defined grouping

And for each Logical Solution Component, you automatically will get an estimate of the time needed to fix and a simple reference to the underlying Custom Code all the way down to code line level. 

Estimate by Logical Solution Component

Assessment and Execution

Assessments will always be done with output from your ECC system, because this is where you prepare for the journey and do the final estimation. So what happens when you kick off the actual project and get going with fixing Custom Code in the new S/4HANA Development system?

The first blind spot you might discover is that setting up a new S/4HANA Readiness Scan in the new Dev. System might result in skipping some very important information. SAP cannot scan Custom Code with syntax errors, so if you look into the Issue list you will find a lot of objects missing. One way to solve this it to go back to the scan from the assessment system and plan based on this, but it far from the ideal way of working.

The Gekkobrain S/4HANA tool will tap into findings from both the assessment system and the new S/4HANA System. And for the initial objects with Syntax Error in the S/4HANA Development system, Gekkobrain will automatically overlay with the latest findings from the assessment system, so you will never overlook any critical Custom Code Objects. 

This also means that you can use Gekkobrain as a project management tool for the code clean-up tasks, since Gekkobrain will scan the Custom Code daily to get a refreshed picture of the progress. You can define sprints, assign developers and use the status management to make sure that you get all the relevant Custom Code fixed. 

Have a nice summer holiday!

Best regards from Mogens Enevoldsen, CTO, Gekkobrain

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