Dynamics 365 Business Central: accessing Early Access Preview in online sandboxes.

With the upcoming 2026 Wave 1 release wave for Dynamics 365 Business Central, Microsoft is finally opening the possibility to create sandbox environments based on the early access preview of the next major release.

The early access preview period coincides with the update period for the major versions, specifically:

• The early access preview for an upcoming April major version (for example v28) starts when the update period for the current October major version begins (for example v27).
• The early access preview for an upcoming October major version (for example v29) starts when the update period for the current April major version begins (for example v28).

During the early access preview period, only tenants that use the Partner Sandbox license can create new sandbox environments on the early preview version. You cannot do that on standard Business Central environments.

The only environment localizations supported for early access preview at the moment are DE, GB, and US. Any Microsoft Entra tenant with a Partner Sandbox license can create these new Early Access Preview environments, but the only limitation for now is that you can create only a DE, GB, US sandbox (at least for the beginning of this launch).

Please note the following rules:

• Early access previews are based on the Microsoft’s development branch of the next release, so environments based on the early access preview version are automatically updated to the latest build of the preview version every Sunday.
• Manage or reschedule this update cadence is not possible.
• Environments that fail to update to the new early access preview build for any reason are automatically deleted and can’t be recovered.
• You can’t update a preview environment to a different version.
• Microsoft will delete preview environments 30 days after the preview version becomes generally available (GA).

I want also to mention that this new Early Access Preview possibility on partner’s sandbox environments does not want to replace Docker containers. With Docker you can access the Early Access release from a long time…

Original Post https://demiliani.com/2025/10/12/dynamics-365-business-central-accessing-early-access-preview-in-online-sandboxes/