Planned Exchange hybrid migrations to Microsoft 365 with controlled coexistence and cutover
We help organisations migrate from on-premises Microsoft Exchange to Exchange Online using a hybrid approach that supports coexistence, staged mailbox moves and operational continuity during transition.
This service designs and implements an Exchange hybrid configuration, manages mailbox migration waves and validates mail flow, identity and client access so teams can move to Microsoft 365 at a controlled pace.
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Service Overview
Highlights
- Exchange hybrid architecture design
- Mailbox migration planning and execution
- Mail flow and coexistence validation
- Cutover and post-migration stabilisation
Business Benefits
- Maintain coexistence between on-premises and cloud mailboxes
- Reduce user disruption during migration
- Enable phased or staged mailbox moves
- Clear operational handover after migration
Typical use cases
- Large organisations migrating mailboxes in phases
- Environments requiring extended coexistence
- Complex Exchange topologies or compliance requirements
- Preparation for full cloud-only Exchange operations
Objectives & deliverables
What Success Looks Like
- Design an Exchange hybrid topology aligned to requirements
- Configure hybrid connectivity and authentication
- Migrate mailboxes in controlled batches
- Complete cutover and decommission legacy components where required
What You Get
- Hybrid architecture and configuration documentation
- Configured Exchange hybrid connectivity
- Mailbox migration reports and logs
- Post-migration validation and handover artefacts
How It Works
- Assess current Exchange environment and readiness
- Configure Exchange hybrid connectivity
- Plan and execute mailbox migration waves
- Validate mail flow, client access and cutover outcomes
Engagement Options
- Hybrid Readiness Assessment
- Hybrid Configuration and Setup
- Mailbox Migration Execution
- Post-Migration Optimisation and Handover
Additional Information
Prerequisites & licensing
Before starting this service, ensure your Exchange environment and identity platform are supported for hybrid connectivity with Microsoft 365.
- Supported on-premises Exchange version
- Microsoft 365 tenant with Exchange Online
- Identity integration using Entra ID or hybrid identity
- Network and firewall readiness for hybrid endpoints
Security & Compliance Notes
- Hybrid connectivity relies on secure mail flow and authentication paths
- Administrative access should follow least privilege principles during migration
Common Bundles
Customers who use this service often bundle with these services
Identity & Access Enablement Workstream
Configure Entra ID conditional access, privileged identity management, and governance features unlocked by E3 to E5 upgrades licensing.
Tenant-to-Tenant Migrations
Plan and execute tenant to tenant migrations across Microsoft 365 workloads, preserving data, identities and access during organisational change.
Modern Work Workshops
Facilitated workshops to improve Microsoft 365 collaboration, productivity, and adoption by aligning scenarios, behaviours, and priorities across teams.
Frequently Asked Questions
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