Only 37% of companies still running SAP ECC expect to be on its replacement, S/4HANA, by the end of 2027.
That is the finding of the 2026 investment report from DSAG, the German-speaking SAP user group. About half plan to finish by the end of 2030 and pay extra for support in the meantime, and 4% do not expect to move until 2033.
The ECC to S/4HANA migration is a multi-year project for most companies, and maintenance has to keep running through all of it.
This guide covers what the migration means for maintenance, which dates apply to you, and what you can do now rather than waiting for the project to finish.
ECC to S/4HANA migration deadlines.
There is no single deadline for migrating to S/4HANA. The date depends on which version of ECC you run, and several other dates sit alongside it.
Every ECC system runs an "enhancement package," which is SAP's term for a major update level. Your IT team, specifically the SAP Basis team who look after the system itself, can tell you which one you have.
The dates below come from SAP's Product Availability Matrix, SAP's official register of support dates for every product version.
Additionally, you may have heard that SAP announced an offer called SAP ERP, private edition, transition option that keeps ECC running from 2031 to 2033.
It comes with conditions:
- You must already be running ECC under RISE with SAP (SAP ERP, private edition).
- The system must be at least 2 TB.
- You must buy SAP's top support tier (aka "max success plan") for the whole period.
SAP says it is not an extension of ECC support and that nothing changes for companies running ECC on their own servers after 2030 (SAP News Feb 2025).
SAP maintenance phases explained.
SAP uses three terms for these phases, and they matter because each one changes what you get and what you pay. The definitions below are from SAP's maintenance strategy.
The cost works like this. Extended maintenance adds two percentage points to your support rate, so a company paying 22% of license value pays 24%, a 9% increase in the support bill.
Customer-specific maintenance costs nothing extra, but SAP Note 52505 states that you keep paying your full maintenance fee while legal changes, support packages, and service level agreements stop.
If you are on enhancement package 5 or below, you should already be in customer-specific maintenance. The system runs and the bill is the same, but the support behind it is thinner.
If you are on enhancement package 6, 7, or 8, you move there automatically in January 2028 unless your company buys extended maintenance or has moved to S/4HANA.
From January 2031, customer-specific maintenance is the only option for ECC.
Other deadlines to keep in mind.
It's not just your ECC system that you'll need to keep an eye on.
You'll also need to look into whether the database under ECC (Oracle, Db2, or SQL Server, for example) has its own support dates set by its vendor, and SAP's ECC dates do not change them (SAP Note 2881788).
What stays the same.
The parts of SAP your maintenance team uses survive the move. Functional locations, equipment records, notifications, maintenance orders, task lists, and maintenance plans all exist in S/4HANA under the same names, as SAP's Maintenance Management documentation shows.
The classic SAP screen (SAP GUI) is not going away either. S/4HANA introduces a browser-based interface called SAP Fiori, and some teams assume they will be forced to switch. They will not. SAP's maintenance strategy for SAP GUI (SAP Note 147519) shows SAP GUI for Windows 8.10 was released in July 2026 with full support to 30 June 2029, and states that SAP will keep providing a supported version of SAP GUI for as long as any application uses the classic screen technology.
What changes.
There are four things worth knowing about.
1. S/4HANA runs on a release cycle.
Unlike ECC, which has stayed on version 6.0 for two decades, S/4HANA releases almost yearly, and each release has its own support window. Which release you land on decides how long you have before the next upgrade.
Companies that moved early, to the 2021 or 2022 release, face an S/4HANA upgrade at the same time everyone else is converting from ECC.
2. Maintenance processes can run in phases.
S/4HANA offers a "phase model" that splits maintenance work into nine fixed phases:
- Initiation
- Screening
- Planning
- Approval
- Preparation
- Scheduling
- Execution
- Post execution
- Completion.
It is optional. SAP delivers it through new order types, so your existing order types keep working as they do in ECC. If your team relies on custom statuses in ECC to control the same flow, the phase model may replace them, or it may not fit. This is a design decision the maintenance organization should make, not the migration project.
3. Customer Service is being replaced.
If any of your work runs through the Customer Service module, known as CS (service orders, repairs on customer equipment, warranty processing), this matters.
In S/4HANA, CS is only available as a "compatibility pack," which means you get temporary rights to keep using it while you move to the replacement, called S/4HANA Service.
Those rights have a fixed end date, and it depends on how you run S/4HANA. According to SAP Note 2269324 (version 102, August 2026):
- If you run S/4HANA on-premise, meaning your own servers or a hosting provider under your own license, CS rights end 31 December 2030.
- If you run it under RISE with SAP, they end 31 December 2033.
Moving CS processes to S/4HANA Service is a separate project from the ECC conversion, and it needs its own plan.
4. Your planning and mobile software has its own dates.
This matters most for maintenance teams and covers several products, so it gets its own section below.
Your maintenance apps have their own deadlines.
The ECC conversion is one project. The planning software and the mobile app your technicians use sit on top of SAP and have their own support windows.
Several of them close before ECC does. All dates below are from the Product Availability Matrix as of August 2026.
Two things stand out.
If your technicians use SAP Work Manager on SAP Mobile Platform, standard support for the platform ends on 31 December 2026. That is a mobile deadline before the ERP deadline, and the ERP project is unlikely to own it.
SAP Service and Asset Manager (SSAM), SAP's current mobile work order app, gets about two years of standard support per version. Whoever runs SSAM is on a permanent upgrade cycle for the mobile app, separate from anything happening with ECC or S/4HANA. Budget and test time for that cycle rarely appears in the migration plan.
If you want to check your own products, ask your Basis team to search the Product Availability Matrix for each one and note two fields: end of mainstream maintenance and end of extended maintenance.
For compatibility packs like CS, the dates are in SAP Note 2269324 instead. The two are different registers and they are easy to mix up.
Where ECC to S/4HANA migrations hurt maintenance.
The technical conversion is IT's job. What your team sees is the app on their phone, the planning software, and the forms. That is where the maintenance cost of a migration lands.
It's common for companies to build or buy a mobile solution that runs on custom code, ECC-specific interfaces, or a low-code platform configured for ECC data structures. When the backend changes the integration has to be rebuilt, retested, and rolled out again to every technician. This hurts your team, who you probably spent a lot of time and effort getting into their current software.
S/4HANA migration is SAP customers' single biggest challenge, with 61% citing budget and 48% citing integration.
The survey data supports this. In ASUG's 2026 Pulse of the SAP Customer survey, the Americas SAP user group found that S/4HANA migration is SAP customers' single biggest challenge, with 61% citing budget and 48% citing integration. In a 2025 ASUG survey, business process change was the top barrier to migration to S/4HANA for 49% of respondents, ahead of any technical issue. Maintenance is a business process with a lot of custom logic and a lot of users and will feel this pain more than most.
The question to ask any third-party vendor is not whether their product supports S/4HANA. Everyone says yes. It's important to ask what has to be rebuilt, who pays for it, and how long it will take to migrate.
Do not stop progress while you wait for S/4HANA.
When a migration is announced, a common reaction from IT is to put every other SAP-related decision on hold.
"We'll look at your new planning software after S/4HANA."
For a project that finishes in six months, that could be reasonable. But it's costly for one that finishes in years.
The answer to "wait for S/4HANA" is to choose software that does not care which one you are on. Three criteria make that possible:
1) No changes to the SAP core. Custom code inside SAP is the thing that breaks during conversion. Software that connects from outside, through standard SAP interfaces, does not have to be rebuilt. SAP calls this approach Clean Core.
2) One integration layer for both ECC and S/4HANA. If the vendor supports both from the same platform, your technicians keep the same app, the same training, and the same habits when the backend changes.
3) Deployment measured in weeks. If it takes a year to roll out, it competes with the migration for the same people and budget. If it takes weeks, it does not.
Find solutions with measurable business value for your company that meet those criteria and the objections from IT should go away.
Where Arkyn helps.
FastCloud, the integration platform behind Arkyn's FastApps, works with SAP ECC and S/4HANA and supports the transition between them.
It connects to SAP through standard interfaces with no changes to the SAP core, so the integration is not tied to one backend release. And it's quick to roll out with most deployments going live in 2 to 6 weeks.
For a maintenance team, that means you can give technicians FastWork or FastPlan on ECC today and keep the same app, the same training, and the same adoption when the backend moves.
So if you are looking to improve the way your team gets work done and are not yet on S/4HANA, get in touch with us and we will help you improve processes even during a migration.