BITSUMMIT consolidated three Microsoft 365 tenants into one governed, compliant environment for Southeast Public Health, with a zero-downtime cutover and full bilingual hypercare.
Southeast Public Health, formerly the South East Health Unit, was operating across three separate Microsoft environments, kflaph.ca, hpeph.ca, and the LGL environment, each with its own identity model, mail flow, and collaboration footprint. That fragmentation slowed collaboration across regions, complicated administration, and spread risk across identity, messaging, and compliance.
Underneath the tenants sat legacy Exchange infrastructure, including Exchange 2010, that constrained cloud adoption and raised real reliability and supportability concerns. Any consolidation had to keep public health teams in service throughout while satisfying PHIPA, PIPEDA, GDPR, and AODA requirements at the same time. The scope went well beyond a helpdesk engagement: it amounted to an ecosystem rebuild that had to unify identity, modernize messaging, and enable secure collaboration without disrupting the people who depend on it.
BITSUMMIT delivered a controlled, zero-downtime tenant-to-tenant consolidation that combined hybrid Exchange modernization, identity reconciliation, and phased migration. Every stage was structured to minimize risk, hold service continuity, and leave the organization operationally ready.
Modernize messaging to hybrid first
BITSUMMIT deployed Exchange 2019 hybrid servers in Kingston and Belleville and established hybrid coexistence with Microsoft 365 for the LGL environment, using the Hybrid Configuration Wizard and modern authentication for secure mail routing. Once coexistence was validated, the legacy Exchange 2010 infrastructure was safely decommissioned.
Reconcile identity before anything moved
The new southeastph.ca tenant was provisioned with the verified legacy domains, and more than 250 duplicate user principal names and proxy addresses were identified and resolved ahead of migration, the kind of conflict that quietly breaks mail flow if it reaches cutover. Azure AD Connect staging supported controlled synchronization, and aliasing and user cutover sequencing were automated to keep identity continuous.
Migrate in waves, with integrity controls
The three tenants were migrated across more than fifteen structured waves, with a 30-day delta-synchronization strategy preserving data integrity as people moved. Exchange Online, SharePoint, OneDrive, and Teams came across with high fidelity, backed by runbooks, rollback plans, and change-board-approved cutover schedules, and DNS, mail flow, and compliance policy were validated after each cutover.
Bring people with it
Alongside the technical work, BITSUMMIT ran weekly change-champion networks and daily go-live huddles, delivered bilingual, AODA-compliant training and recorded walkthroughs, stood up a centralized SharePoint support hub with role-based content, and monitored adoption telemetry to target coaching where it was needed.
The engagement left Southeast Public Health on a stable, compliant, unified Microsoft 365 environment built for long-term public health operations, with the fragmentation and technical debt gone. Three production tenants became one governed environment, and the hybrid Exchange cutover ran with full coexistence during transition and zero downtime.
Because every identity conflict was resolved before migration, there were no post-cutover mail issues, and compliance with PHIPA, PIPEDA, GDPR, and AODA was enforced from day one. Bilingual training, the change-champion network, and a 30-day hypercare window gave staff full coverage through the transition. With consolidation complete, Southeast Public Health is positioned to advance cloud-native service delivery, strengthen security policies, and expand automation across Microsoft 365, with a clear roadmap for continued maturity and no vendor lock-in.
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