Windows Server 2016 and Windows 10 end of support: what UK public bodies' own FOI answers show Aggregate data: public-sector-windows-eol-2026.csv SOURCE Freedom of Information responses from UK public bodies, published online. The requests were made by other people, not by Servnet; Servnet read the published requests and the public bodies' replies and coded the replies. Not a random sample: the bodies are those that happened to receive these requests and reply. Some bodies share one IT estate and gave the same answer. Four sets of requests were used. Each is identified only by topic and period; the code is the value in the batch column of the CSV. IT2024: IT infrastructure requests, November 2024 onwards (270 bodies). 270 requests; sent November 2024 to July 2025 (most on 4 and 12 November 2024). Study questions: which server operating systems are used; whether VMware is used and whether there is a plan to move away from it; whether the body has moved, or plans to move, to Windows 11; whether the device estate is compatible with Windows 11. IT2023: IT infrastructure requests, January 2023 to January 2024 (84 bodies). 87 requests; sent January 2023 to January 2024 (most August to October 2023). Study questions: which server operating systems are used. EOL2025: End-of-life software and hardware requests, June 2025 (28 bodies). 28 requests; sent June 2025 (replies June to August 2025, most in June and July; before Windows 10 end of support). Study questions: a list of unsupported or end-of-life software and hardware, including operating systems; the number of devices running Windows 10. W7XP2021: Windows 7 and Windows XP requests, May 2021 (231 bodies). 231 requests; sent 19 May 2021. Study questions: how many Windows 7 instances or devices are in use; how many Windows XP instances or devices are in use. The questions asked for instances and for devices such as kiosks and laptops; answers mix instances, devices and virtual desktop sessions. A second, later round of the same request was not coded. METHOD Source: Freedom of Information responses from UK public bodies, published online. The requests were made by other people, not by Servnet. Servnet read the published requests and the bodies' replies and coded each body's answers about server operating systems, VMware, Windows 11, Windows 10 and Windows 7/XP against a written codebook. Figures are counts of public bodies, one record per body per batch. One public body per batch. Where a body received two requests in the same batch, the most complete and most recent response is used (IT2023: 87 requests from 84 bodies). Every coded value was taken from the body's own published reply (email text, answers typed into the quoted request, or attachments: PDF text layer, DOCX, RTF, DOC). Answers that exist only on a body's own website, portal or disclosure log were not fetched and are counted as 'referred elsewhere'. Family-level answers such as 'Windows Server, Linux' are never read as 'no old versions'. Response status is judged on the study questions only: exemptions applied to other questions (budgets, contracts, staff names) do not change it. 'Partly answered' means some study questions were answered and others withheld, skipped or referred to a partner. Version shares use as denominator the bodies that named at least one Windows Server release; a body counts once per release it named. Ranges such as '2012-2022' are expanded to every release in the range; open-ended answers such as '2016 and above' count only the oldest release named. Response statuses published for each set: answered; partly answered; referred elsewhere (answer not published with the request); refused (exemption or other refusal); information not held; other (unresolved clarification or hold, supplier-enquiry handling, closed without answer); no substantive response published. Exemption figures are limited to codings that can be verified from the stored quotes: a section is counted only where the stored extract of the reply shows the body applying it to a study question, so the published section 31 count for 2024-25 is a lower bound, and section counts whose codings could not all be verified this way are not published. Two independent verification passes re-checked random samples of records against the source pages; where they found problems, the coding was corrected or the affected figure was withdrawn. Percentages are rounded to one decimal place and may not sum to 100. CAVEATS - Not a random sample. These are the bodies that happened to receive these particular requests from other people and answered them; results cannot be scaled up to all UK public bodies. - Answers are self-reported and dated: May to November 2021 (W7XP2021 figures), 2023 and early 2024 (IT2023), November 2024 to October 2025, mostly November and December 2024 (IT2024), and June to August 2025 (EOL2025). Estates may have changed since. - Many bodies answered only at family level ("Windows Server, Linux") or withheld the answer. Version shares describe only the bodies that named releases, which may differ from the rest. - Withholding is common, and in 2024-25 section 31 (law enforcement: prevention or detection of crime) was the section most often cited for operating-system and version details. Exemption figures count only citations shown in the stored extracts of the replies. Withheld answers are not evidence of old or new versions. - Shared IT services mean some bodies gave identical answers about one estate (for example district councils sharing an ICT partnership). Figures count bodies, not estates, so shared-service answers are correlated. - Presence of a release means it was named somewhere in the estate, not how many servers run it; a body naming Windows Server 2016 may run it on one server or many. - The 2021 Windows 7/XP questions asked for instances and devices; answers mix instances, devices and virtual desktop sessions, so only the share of bodies reporting some or none is published. An answer of 'fewer than 5' is counted as neither. - Windows 10 figures from 2025 are mostly approximate and predate the 14 Oct 2025 end of support; only the number of bodies that gave a figure is published. - Answers held only on a body's own website or portal were not read and count as "referred elsewhere". SUPPRESSION RULES - Any count (numerator) or base (denominator) below 5 bodies is suppressed: the CSV shows '<5' and leaves pct blank. - In mutually exclusive breakdowns (for example response status) small groups are merged into one group, folding in the next-smallest group if needed, so that no suppressed value can be worked out by subtraction from a published total. - A body-type split of a published total is shown only if every group in it has at least 5 bodies and 5 in the count; otherwise groups are merged or no split is published. - Where a whole breakdown would reveal counts below 5, only its base is published. - No body is named, no reply is quoted and there are no per-body rows. Windows 10 device totals and medians are not published. CSV COLUMNS batch: request set code (see SOURCE); measure: what is counted; group: the category; numerator: number of bodies in the group; denominator: the base (number of bodies the share is taken over); pct: numerator as a percentage of denominator, rounded to one decimal place (blank when suppressed). LICENCE Licence: the derived aggregate tables in this study and its CSV download are published under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). The underlying Freedom of Information responses remain the public bodies' information: copyright in each response stays with the body that sent it (or the Crown), and none is republished here.