On 15 October 2025 Microsoft announced that the first-generation B-series will be retired on 15 November 2028. That covers sizes such as B1s, B2s, B2ms and B4ms, which in many environments run small branch servers, jump hosts and test systems.
Several interim dates have been added since, spread across different announcements. For 2027 budget planning they matter more than the retirement date.
15 November 2025: no more three-year reservations
Since that day, three-year reservations for Bv1 can no longer be bought or renewed. Existing ones run until they end.
1 July 2026: no one-year reservations either
Since July the same applies to one-year reservations. Any reservation that expires is not replaced, even with auto-renew switched on. From then on the VM runs at pay-as-you-go rates.
More on this: Bv1 reservations: questions and answers for finance and FinOps
July 2026: Bv1 stops growing
Capacity growth restrictions also apply since July. New subscriptions cannot deploy Bv1, and Microsoft approves no additional quota for existing ones. Within existing quota, VMs can still be created as long as the region has capacity. Quota is a limit, not a promise.
Operationally this means a restore into another subscription, a disaster recovery test or a reorganised landing zone can fail on a Bv1 size that runs without issues day to day. Reservations do not change that. They are a discount, not capacity.
1 February 2027: free reservation exchange ends
Until that day, VM reservations can be exchanged freely into other series. After it, each eligible reservation bought before the deadline keeps exactly one final exchange.
More on this: Bv1 reservations: questions and answers for finance and FinOps
1 February 2027: price adjustment in seven regions
On the same day, prices for specific VM series and storage services rise by 8 to 17 percent in seven regions, by 9 percent in West Europe. Bv1 is excluded; its successors are not on the exclusion list.
More on this: The 2027 price adjustment: why I still advise moving off Bv1
15 November 2028: retirement
From that day Bv1 sizes can neither be used nor purchased. VMs still running are deallocated, stop working and lose SLA and support. How much effort the replacement takes depends mostly on the operating system.
More on this: Replacing Bv1: a six-step runbook
Three questions for IT before the 2027 budget is set
- How many Bv1 VMs run in our subscriptions, and what for?
- When do the related reservations expire, and what does the VM cost afterwards?
- Which of them sit in a region affected by the price adjustment?
The answers sit on three levels: the resources, the billing data and Microsoft’s announcements. If any of these questions cannot be answered within a few days, the basis for a budget decision is missing.
What the cost and migration analysis delivers
The cost and migration analysis answers these questions for your environment and derives a decision for every VM. It takes three to five weeks for a fixed fee.
- An inventory of all v1 to v3 VMs across every subscription
- Reservations with expiry dates and an exchange recommendation before 1 February 2027
- Target size and migration path per VM, based on measured utilisation
- Cost before and after, including the 2027 price adjustment
- A savings plan and reservation recommendation for the target state
Implementation stays with your team or your service provider.
Sources (as of 10 October 2026)
- Azure Update 500682: retirement of the F, Fs, Fsv2, Lsv2, G, Gs, Av2, Amv2 and B series (15 Oct 2025)
- Azure Update 560948: end of Reserved VM Instances for selected series from 1 July 2026
- Microsoft Learn: VM size series retirements, capacity growth restrictions, and modernization guidance
- Azure Update 568514: reservation exchanges for services covered by savings plans end on 1 February 2027
- Microsoft service notification to customers in the affected regions: “Action required: Prepare for specific Azure VM series and Azure Storage service price updates in seven Azure regions globally” (email, no public link)