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Author's profile photo Rainer Zilch

SAP Business Connector Migration 1: ELSTER/ERiC Scenarios

Objective of this blog post is to give an outlook for customers running ELSTER/ERiC scenarios on SAP Business Connector and guidance for replacing it with a more contemporary platform.


What are ELSTER/ERiC scenarios?

ELSTER (“Elektronische Steuererklärung”) is a joint project of the German Federal Tax Administration and the tax administrations of the German Federal States that has made the electronic transmission of tax data possible. The data is transferred to a middleware where it gets encrypted, signed and then transferred to the financial authorities. ELSTER integration solution for SAP have been available for more than 15 years.

ERiC (ELSTER Rich Client) is a bunch of C libraries provided by the tax authorities that is used for encrypting and signing the data in the middleware. It is the current technical basis for the ELSTER scenarios.


Supported Platforms

SAP supports ELSTER on various integration platforms: SAP Integration Suite, SAP Process Orchestration and SAP Business Connector. The functional scope is the same on all supported products. The reason why SAP supports the different platforms is the intention to offer a solution to any customer in the first place.

When ELSTER started, IT landscapes often were less closely integrated and there was a certain number of customers who did not have a central integration platform in place or used a third-party product. For those customers the SAP Business Connector was a good choice, because it was free of charge, available for most common operating systems and easy to install.

Due to the increase of integration requirements over the years most customers have introduced platforms such as SAP Integration Suite or SAP Process Orchestration meanwhile. Some of them are still running ELSTER on SAP Business Connector for historical reason. Which does not make sense when a more modern integration solution is in place, as it causes unnecessary variety in their landscape. SAP Process Orchestration is still supported but the end of maintenance is announced already. Therefore, it is highly recommended to switch to SAP Integration Suite which is the future-prove solution.


Replacing SAP Business Connector in ELSTER scenarios

Strictly speaking switching ELSTER scenarios from SAP Business Connector to SAP Integration Suite is not even a “migration”, as no content or logic needs to be moved from SAP Business Connector to the new platform. It is rather a re-configuration. And as ELSTER is a widely used standard-scenario it is one that is well proven and documented.

What you need for setting up ELSTER scenarios in SAP Integration Suite is

  • The ELSTER Adapter for SAP Integration Suite that comes as an integration package and that allows you to connect as a client to the ELSTER server.
  • The integration package(s) for the scenario(s) you intend to use, that is
    • SAP HR Integration with ELSTER ERiC for Germany, for LStA, LStB, and ELStAM or
    • SAP Finance Applications Integration with ELSTER, for UStVA


You can easily identify these packages with search term “ELSTER” in the Discover – Integrations feature in SAP Integration Suite.


ELSTER packages


The integration packages contain the technical artifacts required (e.g. the ERiC libraries) as well as implementation guides that describe how to set up the scenarios in detail. As this information is publicly available already it is not subject of this blog.

SAP Integration Suite uses the same certificates in the communication with the authorities SAP Business Connector is using. When setting up the scenarios make sure you have your certificates at hand and know your passwords.


So basically, the steps that need to be performed are:

  1. Identify the required Integration Packages as shown above.
  2. Copy them to your environment.
  3. Read the ELSTER Adapter documentation and the Implementation Guides for your scenarios thoroughly.
  4. Make sure you meet all prerequisites described in there.
  5. Make sure you have your certificates and passwords available.
  6. Configure the scenarios as described in the Implementation Guides.


Each of the ELSTER scenarios provides a test report/transaction so that you can validate your setup.

Once you are done, you don’t need to worry about approaching end-of-support dates and outdated technologies anymore.


Relevant Links, Notes and Blogs

What happens next with SAP Business Connector?

SAP Business Connector landing page

1094412 – Release and Support Strategy of SAP Business Connector 4.8

Cloud Integration – Usage of the Elster Adapter

2558316 – ELSTER: Information about the conversion of communication (ERiC)

1515223 – SAP Process Integration and SAP Process Orchestration: Release Recommendation


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      Author's profile photo Stefan Gass
      Stefan Gass

      The SAP Business Connector homepage (or landing page) is .
      The currently mentioned landing page is rather the SAP Business Connector download page for software updates.

      Author's profile photo Rainer Zilch
      Rainer Zilch
      Blog Post Author

      Thanks for the hint. I have corrected the link.

      Author's profile photo Morten Wittrock
      Morten Wittrock

      Holger Himmelmann, we talked about this recently 🙂 I love that SAP Business Connector is still supported. Having said that, it really does make sense for SAP Business Connector users to look towards a more modern integration platform at this point.

      Author's profile photo Ulrich Schmidt
      Ulrich Schmidt

      Why would you want to replace the Elster SAP Business Connector solution? For most customers, it's still the best one available:

      • no extra license fees
      • very low hardware footprint (if you use SAP BC only for Elster, it can basically be installed as a background process on one of the application servers of the SAP system -- then it needs no extra hardware at all)
      • best performance: according to my tests, the current SAP BC solution is 17% faster than the generic JNA "Java <--> C interaction" that comes with the ERiC package and which is used by PI/PO as well as by CPI. My tests were run on the same hardware (so this doesn't even take the next point into account, which would increase the performance advantage of the SAP BC solution even more, as an extra communication step always means increased response times.)
      • most robust solution: why communicate in a triangle (on-premises network --> SAP Cloud --> Elster Servers), when you can communicate in a direct line (on-premises network --> Elster Servers)?


      Also, I object strongly against your term "outdated technologies". I'm not sure whether you are aware that the latest release of SAP BC has just been delivered in 2021, and it has therefore been updated to the latest technologies (same operating systems and Java versions as used by PI/PO and CPI).
      Or what else do you mean by "outdated technologies"? The main technologies that SAP BC uses for communication, are RFC and HTTP. If you call these outdated, because they were invented in the 80s (HTTP) and 90s (RFC), then you are right, but PI/PO and CPI use these technologies as well!

      So if there is no difference in terms of OS, Java and used communication & encryption protocols between SAP BC and other middleware tools, it is incorrect to talk of "outdated technologies" -- especially in the context of Elster, where the only technology that matters is contained in the ERiC libraries, and these are identical in all Elster solutions...!


      Finally I want to point out an incorrectness in your blog:
      "In 2019 the new solution ERiC was released."

      This is wrong. The ERiC libraries have been released in the late 1990s. (According to Wikipedia: first delivery of the Elster Client Library to 12 German tax software providers in Oct. 1997.)

      Then in 2017, the German tax authorization announced, that it would shut down the alternative "Offene Schnittstelle", and everyone would have to use the ERiC solution. SAP BC supports the ERiC solution since end of 2017.

      2019 was only the date, when the "Offene Schnittstelle" was finally shut down by the German tax department.

      Author's profile photo Morten Wittrock
      Morten Wittrock

      Hi Ulrich

      I think it is safe to assume that for the vast majority of customers, SAP Business Connector is no longer enough to cover all their integration needs. So let's assume accordingly, that if a customer still runs their ELSTER integration on SAP Business Connector, they also run another integration platform, which is likely either SAP PO or SAP Cloud Integration (or maybe both).

      So when you ask "Why would you want to replace the Elster SAP Business Connector solution?", I think the more pertinent question is: Why would you run your ELSTER integration on a separate platform?

      Even though there is no license fee and the hardware footprint of SAP Business Connector is small, it is still a platform that must be maintained, monitored, patched etc. So assuming the customer also runs one of the other platforms, it makes a lot of sense to run the ELSTER integration there and have one less platform to worry about.

      This doesn't mean that SAP Business Connector is not a good product! It obviously is or it would not have survived for two decades.



      Author's profile photo Ulrich Schmidt
      Ulrich Schmidt

      Hi Morten,

      I agree completely with you on the point that it doesn't make sense to use a separate platform for Elster. If you are already using one or the other for other integration tasks, then yes, reuse it for Elster. No need to learn, setup and maintain an additional integration platform!

      However, I think that there is a large number of customers, who don't have any integration needs and just need something for Elster. For these cases, my recommendation would still be to use SAP BC, simply because it is much easier to learn and to operate. (And therefore much cheaper in the end.) In my opinion, using PI/PO only for Elster, is like shooting sparrows with a cannon. 🙂

      It can be expected that as long as the ERP backends are supported, which implement Elster via BC, SAP will also support the BC. Currently, extended maintenance for e.g. SAP ECC 6.0 runs until 2030. So there shouldn't be any problem with using that setup for another 7 years. (It's probably quite a bit of money that can be saved in those 7 years.) And no one knows, what will happen after that time... The first time that SAP BC had been "declared dead", was in 2002... But nevertheless, SAP shipped new SAP BC releases in 2003, 2008 and 2021.

      But I disagree with your statement "I think it is safe to assume that for the vast majority of customers, SAP Business Connector is no longer enough to cover all their integration needs." I have the impression, that you are still thinking about the old SAP BC release from 2008? Have you already taken a look at the latest 4.8.1 release from 2021? It is a major overhaul of many internal components, everything was ported to Java 8, Developer was updated to support today's high definition screens (I'm running it on a 3840x2160 UHD display, and it works perfectly...!), many performance & stability improvements, and even quite a number of new features sneaked in. (More on that later.)
      With the 2021 update, SAP BC is still ready for the majority of "standard" integration tasks.

      Of course you have a point, when you say that for most people it is too much effort to learn, maintain and monitor two different integration platforms. However, it can also be an advantage (or a necessity). A good craftsman has more than one tool in his tool chest. If he says "I don't want to learn how to operate a screwdriver, I do everything with my hammer", he will be a bit limited in the kinds of tasks he is able to perform. If you have the luxury of being able to choose between two options, the number of tasks you can accomplish in an elegant and efficient way (or at all...) is much higher.

      In my experience, there is only an 80% overlap between PI/PO and BC functionality. E.g. if you want to publish or consume a state-of-the-art WebService interface, you need to use PI/PO (or the WebService Engine built into the SAP ABAP stack). It is true that the WebService engine of the SAP BC is still the 2002 version. (Which makes perfect sense, by the way: it's a lot of effort to keep a WebService engine up-to-date, and as SAP already has two implementations in PI/PO and in the SAP ABAP stack, why invest into a third one?) But other components of the SAP BC have been kept up-to-date and are still useful today.

      A few examples of functionality provided by SAP BC, but not by PI/PO/CPI:

      • Web Automation: you can write scripts that automatically "crawl" through web pages and extract information from HTML pages. (One sneaky application: browse through your competitor's online web catalogue and extract pricing information... ;-))
      • Integration with C/C++ components. (And as most programming languages have a C interface, you can also integrate with all kinds of components. One example I remember: someone had the need to integrate a SAP System with an old component written in Cobol. As we all know, the HTTP protocol was invented by Tim Berners-Lee in 1991, and that Cobol system was written before that, so of course it didn't have any HTTP interface, let alone "XML"... We wrote a small C wrapper that called into the Cobol routines and could be plugged into the SAP BC and then called from ABAP via RFC.)
      • The following concerns only CPI: There are a few scenarios, where from a technical point of view it doesn't make sense to use CPI. For example, assume you want to exchange data between your SAP system and a third party system, which both run side by side in the same room of your on-premises data center. If you were to use CPI for this integration task, it would mean, that the request data would first be sent via Internet to CPI in the SAP Cloud, CPI would transform it and then send it across the internet a second time, back to your data center, the response data would then be sent from the third-party system to CPI, getting transformed there and then being sent over again to the SAP System in your data center...

        So even though, the two systems are located right next to each other and are connected by a 2m LAN cable, we are sending the data across the world wide web 4 times! That will have a huge performance impact (especially when we are talking about mass data processing), and would also be an unnecessary security risk (the hackers out there in the internet get 4 chances at attacking your data...)

        In such a scenario, it would make much more sense to install a SAP BC, either on the SAP server or on the server of the third-party system, and implement a direct connection inside your LAN! (You could also use PI/PO here, though that would probably mean setting up a third server in addition to the two servers of SAP System and third-party system.)

      • WebSocket-RFC: as you might know, SAP published a new RFC protocol, "WebSocket-RFC", which can be used to make RFC calls easily via HTTP Proxies/firewalls. This protocol is available with the latest SAP Kernels, and has also been built into SAP BC 4.8.1. (So it's a brand new feature!) If you have an S/4HANA System or a Steampunk System running in the Cloud and an ERP system running on-premises, you would use WebSocket-RFC for making RFC calls between these two.

        But what do you do, if your ERP system runs with an older SAP Kernel release that does not yet support WebSocket-RFC? SAP's official recommendation for this use-case is then to install a SAP BC next to your ERP system (or re-use an existing one, e.g. if you already use one for Elster). The ERP system then communicates with the SAP BC in "classic RFC" protocol, SAP BC converts it to WebSocket-RFC and uses your HTTP-Proxy to send it outside your firewall to the S/4 / Steampunk system in the Cloud.
        Note: there are no plans to support WebSocket-RFC in PI/PO. And for obvious reasons, CPI wouldn't be the right choice for this setup, because you would end up making classic RFC calls across the internet (meaning you would have to open the necessary ports for RFC in your firewall, which is not safe to do...), and the whole point of this exercise is to avoid that... 🙂

        Certainly no one will switch their SAP applications to the Cloud in a "big-bang". There will be quite some time, where hybrid solutions with S/4 / Steampunk systems in the Cloud and older ERP Systems in on-premises data centers will co-exist. And during that time SAP BC is again SAP's recommend go-to solution for enabling RFC communication between Cloud systems and older ERP systems.

      So as you can see, SAP BC is an "old work horse" that doesn't even think about any such thing as "retirement"... It still has a lot of milage in it (especially after the 2021 update), and if you can put it to good use helping you achieve tasks that would otherwise be much harder or even impossible to achieve, then why shouldn't you?

      To quote Mark Twain: "The report of my death was an exaggeration."  🙂

      Best Regards, Ulrich