Leaving Microsoft, 5/7: funding the transition years

On 4 December 2025, Schleswig-Holstein’s government announced a milestone in its move away from Microsoft. Almost 80% of workstations outside the tax administration were now using LibreOffice, it said. Its statement put two figures alongside each other: more than €15 million saved on licences, and €9 million of one-off investment planned for 2026 in migration and open source development. Together, they presented an encouraging picture. Understanding what they measure requires opening the budget documents. ^[1]

Those documents describe a transition extending over several years. The €15 million concerns a renewal that was avoided. The €9 million funds a stage of the work. A separate parliamentary answer puts expected recurring savings at more than €5 million a year, starting no later than 2030. In the intervening years, staff must keep processing cases while IT teams rebuild services and, where necessary, run several environments together. ^{[2] [4]}

After contracts, cloud licences and business applications, this fifth instalment follows the money and work required to leave. Funding the transition matters as much as the eventual operating budget. A government’s commitment to digital sovereignty has to survive several budget cycles before its intended benefits can be assessed.

Fifteen million over what period?

The budget response of 3 December 2025 explains the first figure. The state estimates that it avoided around €15 million by declining to renew Microsoft Office and Outlook licences with Software Assurance, the accompanying contractual coverage, for approximately 80% of workstations outside the tax administration. It estimates a full renewal for the workstations covered by that scenario at roughly €18 million. The passage does not specify the period the licences would have covered. The following day’s statement repeats the licensing saving without describing it as annual. ^{[2] [1]}

Avoided expenditure depends on a comparison: what the government estimates it would have bought had it continued with its existing environment. Checking that estimate requires the products, workstation count, renewal terms and period covered. Establishing a net annual saving requires a further comparison with the alternative’s recurring costs. The announced figure alone cannot supply all of that information. The distinction follows the British Treasury’s Green Book approach to the baseline scenario, investment costs and operating costs. ^[5]

The €9 million covers something different. In the same December 2025 documents, it represents one-off expenditure and investment planned for 2026 in migrating and developing central services and their infrastructure. The text also discusses consolidating teachers’ and schools’ accounts, already hosted in an Open-Xchange instance, onto the state’s infrastructure. The planned funding covers a defined stage of the programme, with a narrower scope than replacing Microsoft entirely. ^[2]

The annual outlook appears elsewhere. On 21 October 2025, the government had set out an efficiency assumption comparing licensing and operating costs in the old environment with those of the sovereign workplace. It expected recurring savings of more than €5 million a year, starting no later than 2030, with some benefits possible earlier. This estimate covers more than the Office renewal alone. At the date of this investigation, it remains a forecast. ^[4]

The documents therefore provide three useful indications: a purchase the state decided against, funding to continue the transition and a target for future operations. A break-even date would require putting them on a common timeline and completing the costs of each scenario.

What the next budget reveals

A response to questions on the draft 2027 budget, submitted on 21 September 2026, gives a more detailed picture. For 2024 and 2025 combined, the government reports €2.495 million in LibreOffice costs, covering development, training, change management and migration. Project services, development, migration and training for the Open-Xchange email platform account for €15.5766 million across the same two years. ^[3]

The response also reports costs incurred in 2026 to that point: €253,000 for LibreOffice, mainly development, and €1,674,700 for Open-Xchange project services and development. This second period is incomplete. The document states that operating savings from the former Exchange platform will come later. Licensing savings involving Windows, Active Directory and SharePoint are also described as future benefits. ^[3]

Figures, calculation and limits

Source: budget response 20/7214 of 21 September 2026, page 3. Original values converted from thousands to millions of euros: LibreOffice, €2.495m in 2024–2025 and €0.253m in 2026 up to the response date; Open-Xchange, €15.5766m and €1.6747m. The bars use these exact values on a common linear scale; labels are rounded to two decimal places. Two complete years combined and one partial year appear in separate groups. The scope covers the items described in the response for these two projects. It provides neither the full cost of leaving Microsoft nor a measure of net savings. [3]

These costs make the replacement work tangible: an email service has to be installed, adapted, migrated and made usable. Their scale warrants following the programme’s funding over several years. Comparing them with the €15 million in avoided licences would first require matching the dates and services covered. The documents reviewed leave that task incomplete. Adding the published costs would describe this subset of the work; it would establish neither the programme’s net saving nor its net loss.

The hours absorbed by government departments

One of the most revealing passages in the German documents concerns what was not measured. Asked about migration costs in October 2025, the government acknowledged additional work in ministries and their subordinate bodies. It could not quantify that work because it had not been recorded during the transition. The same answer noted that a move to Office 2024 would also have required staff training. Learning takes time under several possible paths, and its extent needs to be assessed for each. ^[4]

Consider an illustrative case: an experienced employee helps colleagues adapt their letter templates. Their salary was already in the budget, but days devoted to the migration use a resource that could have gone towards other work. This is an opportunity cost, the value of the use that has been forgone. Paying for cover or overtime adds a budgetary outlay. The Green Book distinguishes effects on payments from the economic use of resources. Both views help explain the transition; adding them carelessly would count some costs twice. ^[5]

Toulouse’s experience shows how this work reaches individual teams. In a study published by the European Open Source Observatory, OSOR, in July 2014, former digital affairs councillor Erwane Monthubert reported office software licensing costs of €1.8 million every three years, against approximately €800,000 spent on migration. She claimed a €1 million saving over the first three years. That is the calculation reported by a person responsible for the project. The document also states that the IT department carried out the migration internally, without providing a quantified breakdown. ^[6]

The same study describes volunteers trained within departments who then helped colleagues. Some staff kept Word alongside LibreOffice for several years because of macros or complex documents. This flexibility helped work continue while extending the period in which both suites remained in use. The historical account raises questions that remain relevant: who supports users, for how long, and how is that responsibility accommodated within their ordinary work? It supplies no price that can simply be transferred to a government organisation in 2026. ^[6]

The last bill depends on the last use

At the start of a migration, an organisation funds its new solution while the old one continues to deliver the service. Access, backups, support and connections to applications awaiting their own adaptation may still be needed. The British Cabinet Office’s guidance on legacy IT explicitly requires the business case to account for parallel running and the time needed to retire the old system, including partial retirement. ^[7]

A recent French finding illustrates this overlap. In its report published in 2025 on the sovereignty of government information systems, the Cour des comptes records the education ministry’s choice of Collabora Online for collaborative office work and hosting in an interministerial data centre. During the gradual rollout, the ministry continued using Microsoft software and services. The Court defines the programme’s scope: collaborative tools, excluding business applications among other categories. Funding an alternative leaves a further question about the uses and contracts that remain in the previous environment. ^[8]

How to read the mechanism

An explanatory l0g diagram based on the Green Book 2026, the Cabinet Office’s March 2022 guidance and Munich’s 2018 office migration documents. The stages represent building the alternative, validation, gradual migration and retirement of the existing system; their widths measure neither time nor cost. Reducing a contract depends on which licensed rights are no longer needed and on the applicable terms. A partial migration may leave part of the old service running. The figure describes an organisational mechanism, rather than an observed Schleswig-Holstein timetable. [5] [7] [9]

The practical question is which use has to end before a cost can actually stop? A document template awaiting revision, a business application still connected to Outlook or a contractual deadline can move that date. A high share of migrated workstations indicates technical progress. Savings that release money from the budget also depend on what the organisation can retire, reduce or stop renewing. An exit plan needs to connect those two timelines. ^[7]

Speed requires judgement too. In the documents prepared in 2018 for Munich’s move from LibreOffice to Microsoft Office, KPMG assesses several migration speeds. Its recommended gradual scenario keeps both environments running for longer. The consultancy nevertheless considers that it better accommodates dependencies between departments, allows lessons from the first waves to be applied and limits disruption. The direction of travel is the reverse of Schleswig-Holstein’s. The economic mechanism remains instructive: shortening the overlap can require more resources immediately and increase the risks of the switch. ^[9]

The report also sets out the limits of its assessment. Its delivery timetable was shortened, data collection was interrupted and some checks were only partial. KPMG states that these constraints affect the quality of its estimates. The document explains assumptions behind a decision in 2018; it does not measure what was ultimately spent. Its disclosure shows why the precision of a financial result must be assessed against the quality of the data behind it. ^[9]

Staying has a trajectory too

Assessing a departure requires describing what would happen to the service if the government retained its supplier. The 2026 Green Book calls this reference point the business-as-usual scenario. It has its own costs, benefits and risks. The guidance also warns that inflating its costs would artificially favour the proposed change. ^[5]

In its March 2023 report on digital transformation, Britain’s National Audit Office documented costs that can be scattered around legacy systems: manual workarounds, additional interfaces and support services. Its findings concern the British public sector systems studied, regardless of supplier. They encourage organisations to identify what they already spend to keep a service functioning. A fair comparison must also assign the alternative the costs it will create and the functions it must maintain. ^[10]

In the German case, the government expects that remaining in the Microsoft environment would entail substantial expenditure on migration and adaptation to the cloud, which was not yet included in its October 2025 efficiency calculation. That expectation belongs to its technological scenario. The cited documents establish no general requirement for every public body to follow the same route. The licensing rights and architectures examined earlier in this series need to be checked for each organisation. ^[4]

The decision concerns future spending. Amounts already paid and no longer recoverable, known as sunk costs, belong in the historical account. The Green Book recommends excluding them from the forward-looking decision while assessing resources that remain usable. Equipment that can be sold, a licence that still serves a purpose or a team capable of managing the transition may retain value for that decision. ^[5]

With that baseline established, sensitivity testing makes the budget more informative. Teams can examine what happens if adapting an application takes longer, the existing contract has to be extended or the new service needs more support than expected. These questions need figures from the project under consideration. The Green Book specifically recommends identifying assumptions whose variation could change the decision. ^[5]

The charges that legislation can remove

The EU Data Act addresses one part of the cost. For the data processing services it covers, Article 29 provides for switching charges to end from 12 January 2027. The definition distinguishes those charges from normal service fees and early termination penalties. The regulation also provides special rules for certain services, including some developed to order and unavailable in the catalogue. ^[11]

This rule acts on what a provider can charge for switching. Training, application adaptation and operation of the destination service still require work and funding. Article 30 also specifies that providers are not required to develop new technologies or services. A transition budget therefore needs to distinguish the charges addressed by the law from the resources required to restore a working service elsewhere. ^[11]

The budget needs to leave a team in place

The work continues after the final switch. The German response of September 2026 still envisages LibreOffice development spending in subsequent years. Control over code, operations or interfaces requires people who can fix, update and improve the service. The British legacy IT guidance recommends setting aside time and money for maintenance and considering reinvestment of some savings in future modernisation. ^{[3] [7]}

In an account of the French Gendarmerie’s experience presented in September 2014, Colonel Xavier Guimard framed this as a capability: outsourced maintenance had to be capable of being brought back in-house. His presentation linked that aim to limiting technological diversity. Retaining the option calls for skills, usable documentation and the ability to take over the work. The document is a programme manager’s account, rather than an audit of the full cost. ^[12]

The evidence suggests two requirements for an exit budget. It should make the cost of maintaining the service through transition visible, including internal work and periods of parallel operation. It should also explain what the administration will be able to maintain and develop afterwards. Funding that capability gives practical substance to the sovereignty it is seeking.

Taxpayers can then assess a trajectory: spending incurred, renewals avoided, savings actually recorded and resources retained to operate the alternative. As these figures become comparable, the administration can adjust its timetable and account for its choices. That continuing assessment is what can turn a savings promise into a verifiable result.

Continue the investigation: what makes a migration last, from testing applications together to maintaining the software over time.

Sources and limits of the investigation

Documentary investigation with a cut-off date of 9 October 2026. We compared government announcements with parliamentary and budget responses, read the original tables and distinguished reported costs, avoided expenditure and forecasts. The Schleswig-Holstein documents cover different scopes and do not provide an audited total cost. The September 2026 source covers a year still in progress; it cannot, by itself, update every earlier assumption. Toulouse, Munich and the Gendarmerie are historical cases used to examine mechanisms. We calculate no break-even date or extrapolated migration cost. The overlap diagram explains a process without simulating expenditure.

1. Schleswig-Holstein, LibreOffice ersetzt Microsoft, statement of 4 December 2025. Workstations outside the tax administration, announced licensing savings and one-off investment planned for 2026. Government source; the statement does not annualise the €15m.
2. Schleswig-Holstein, Umdruck 20/5672, 3 December 2025, pages 4–5. Office/Outlook renewal with Software Assurance, scope of the roughly €15m avoided, €18m full-renewal scenario and planned investment for 2026. Amounts in the table are budget planning figures.
3. Schleswig-Holstein, answers on the draft 2027 budget, Umdruck 20/7214, 21 September 2026, pages 3–4. Reported LibreOffice and Open-Xchange costs for 2024–2025 and 2026 to date; development expenditure and future savings. The document expresses amounts in thousands of euros.
4. Schleswig-Holstein, Drucksache 20/3678, 21 October 2025, pages 3 and 5. Additional work unquantified because it was not recorded; training also required under Office 2024; projected recurring savings above €5m a year starting no later than 2030; the government’s scenario for remaining in the Microsoft environment.
5. HM Treasury, The Green Book 2026, updated on 5 February 2026. Baseline scenario, paragraphs 4.14–4.19; appraisal period, 6.9–6.13; costs and maintenance, 6.29–6.32; financial analysis, 6.86–6.88; sensitivity, 6.102–6.105. British methodological guidance used here to explain comparisons.
6. Cyrille Chausson, OSOR, Toulouse saves 1 million euro with LibreOffice, 23 July 2014, updated on 15 October 2017, archived document. Interviews with Erwane Monthubert and Bertrand Serp; section on licences, internal migration, training of departmental volunteers and exemptions. Savings are those claimed by the officials interviewed.
7. Cabinet Office, Commercial and supplier management approach to mitigating and preventing legacy IT, March 2022, pages 6–7, 10 and 17. Parallel operation, lifecycle, partial or complete retirement, maintenance and funding for future modernisation.
8. Cour des comptes, Les enjeux de souveraineté des systèmes d’information civils de l’État, findings adopted on 11 September 2025, published in October 2025, printed pages 47–49. ETNA programme, selection of Collabora Online and interministerial hosting; continued Microsoft use during deployment.
9. KPMG, Analyse und wirtschaftliche Bewertung der Umstiegsszenarien von LibreOffice auf Microsoft Office, 6 September 2018, public version marked “Entwurf” (draft), pages 4–6 and 27–31; City of Munich, dossier 14-20/V12537, meeting of 17 October 2018, pages 12–17. Migration scenarios, parallel operation, learning and stated limitations of estimates. Forward-looking studies from 2018.
10. National Audit Office, Digital transformation in government: addressing the barriers to efficiency, 10 March 2023, summary, pages 5–6. Dispersed costs around legacy systems and process transformation; findings concern the British public sector examined.
11. Regulation (EU) 2023/2854, Data Act, 13 December 2023, Articles 2(36), 29, 30(6) and 31. Definition and removal of switching charges, distinction from normal service fees and termination penalties, technical limits and special rules. Text accessed on 9 October 2026.
12. Colonel Xavier Guimard, Logiciels libres : retour d’expérience sur une migration à grande échelle dans la Gendarmerie nationale française, 17 September 2014, pages 5–6. Signed presentation hosted by Libricks: ability to bring outsourced maintenance back in-house and technological diversity.