Windows Server 2016 end of support: what hotels need to do before January 2027

Part 1: Two lifecycle milestones and what "end of support" means

The end of extended support does not switch the server off. On the morning of 13 January 2027, the front desk will still check guests in and out as usual. What changes is that the server no longer receives regular security updates or technical support from the vendor; ordinary bug fixes already stopped when mainstream support ended. Every new vulnerability discovered after that date will stay open on the server that holds the hotel's guest data, revenue and receivables.

Part 2: A 15-minute checklist

The person in charge of IT can do this in one morning. The executive team just needs to read six answers.

• 1. Which version is the server's operating system? On the server, press Windows + R, type winver, then press Enter.
• 2. Which version is the database? If it is SQL Server, the administrator runs the command SELECT @@VERSION in the database management tool.
• 3. What year was the server bought, and is the hardware warranty still valid? Hard drives and power supplies are usually the first parts to wear out on a machine that has run non-stop for years.
• 4. When was data last test-restored from a backup? If a backup has never been test-restored, nobody knows whether it can actually be used.
• 5. Who holds the server administrator password? If a single person does, or that person has left the company, that is already an operational risk.
• 6. When does the maintenance contract for the management software expire, and has the vendor confirmed that the version in use runs on the new operating system? Put this question to your current vendor in writing.

Part 3: Why this is a matter for the executive team, not just the technical department

• Guest data is a legal responsibility. The Law on Personal Data Protection No. 91/2025/QH15 took effect on 1 January 2026. A server that holds the names, identity document numbers and phone numbers of tens of thousands of guests without security updates is a weak point the hotel will have to account for itself if an incident occurs. See also the article on personal data protection for hotels.
• Revenue and the books sit on the same server. A server incident in the middle of the peak season does not just paralyse the front desk; it also interrupts the night audit, invoicing and receivables reconciliation.
• The decision touches the budget and contracts. Upgrading, buying extra security updates or switching systems all mean spending and multi-year commitments. The person in charge of IT can make the proposal, but the signature has to come from the executive team.

Part 4: Three options before January 2027

No single option is right for every hotel. The table below puts the three choices side by side so the executive team can compare them within the same framework.

With option A, the most important question is not about the server but about the software: is the version in use still being developed by the vendor? Upgrading the server platform for software that has stood still merely pushes the problem a few years down the road.

Part 5: Two pressures that come with 2026

Compliance: Circular 99, e-invoices, guest stay reporting

Circular 99/2025/TT-BTC took effect for enterprises on 1 January 2026: the chart of accounts has changed and balances have to be carried over. E-invoicing and guest stay reporting have to run smoothly every day. With on-premise software, these updates depend on the vendor's release schedule. On DiHotel, the DiACC accounting module already runs on the Circular 99 chart of accounts and posts revenue from the front desk automatically; e-invoicing is connected; and guest stay reporting data is exported in the required format for front desk staff to submit to the reporting portal. Details are in the article on hotel chain accounting under Circular 99.

Seeing the figures remotely

When the server sits at the hotel, owners usually wait for spreadsheets to be sent up, or phone to ask. DiOwner is a read-only phone app for owners and GMs, with figures that match the operating system, usable for a single property or a whole portfolio on one multi-property hotel management software.

Part 6: If you choose to switch — how to avoid disrupting operations

Large hotels are rarely afraid of the price. They are afraid of a switch that breaks down halfway. The four principles below remove most of that fear.

• Run a trial on a copy of the data first. Nothing is written into the live system. Print a reconciliation table for each group of data for the chief accountant to approve; if a single line does not match, nothing is migrated.
• Close the old books, open new ones. For historical partner receivables, just the opening balance is carried over, one line per partner, with a detailed statement and a record signed by both parties. Folios of in-house guests and deposits for future bookings must be carried over, each attached to the right booking.
• Run in parallel. The old system is kept in read-only mode for a period for look-ups, not switched off immediately.
• Choose the date. The survey and trial run can start right away, because they do not touch the live system. The go-live date should fall at the start of the low season.

The tool for migrating data from on-premise software to DiHotel is already in real use. At one property, it processed more than 60,000 guest profiles and more than 5,000 bookings in under 15 minutes of machine time, with a 100% match and the option to roll back. That is the result of a single run, not a time commitment for every hotel: the whole project usually takes 2–3 weeks, depending on the size of the property and how clean the data is. A detailed 10-step list is in the article hotel management software migration checklist.

Part 7: The "Zero-Cost Switch" package

For hotels with 50 rooms or more, or chains with 2 or more properties, currently running an older on-premise system and signing a contract up to 30 June 2027, DiHotel makes five commitments:

• 1. Data migration at zero cost: a trial run first, reconciliation by data group, with a rollback point.
• 2. Parallel run: the old system is kept read-only for 3–6 months, with no pressure to switch it off.
• 3. No paying twice: the remaining term of the old system's contract, up to 6 months, is added to the DiHotel subscription term.
• 4. A closing-balance record signed by both parties before go-live.
• 5. Training by department, with written operating instructions and video recordings of the training sessions.

The DiHotel subscription for switching customers is no higher than the maintenance fee the hotel currently pays for its old system, calculated by the number of rooms and the modules used. We do not discount the subscription; that amount goes into removing the risks of migration. Detailed terms are set out in the contract.

When does support for Windows Server 2016 end?

According to Microsoft's lifecycle schedule, mainstream support for Windows Server 2016 ended on 11 January 2022 and extended support ends on 12 January 2027. Extended support for SQL Server 2016 already ended on 14 July 2026.

Will the hotel management software stop working when support ends?

No. The server and the software keep running normally on 13 January 2027. What changes is that the server no longer receives regular security updates, so each new vulnerability discovered after that date will not be patched.

How can we find out which version the hotel's server is running?

On the server, open the Run box with Windows + R and type winver to see the Windows version. For a SQL Server database, the administrator runs the command SELECT @@VERSION in the management tool. If nobody can access the server, that is already a risk that needs to be dealt with.

Should we buy extended security updates instead of switching systems?

A paid extended security updates package buys time; it does not solve the root problem. It makes sense when the hotel already has a clear plan to switch systems but cannot complete it before the end-of-support date.

How long does it take to switch hotel management software?

With DiHotel, a system switch project usually takes 2–3 weeks, depending on the size of the property and how clean the data is. The trial run and preparation should start now, while the go-live date should be set in the low season.

Does switching systems mean we have to move to the cloud?

No. DiHotel runs in the cloud, on premise or as a hybrid. The hotel chooses according to the owner's data policy and the quality of its internet connection.