Calico Homes partnered with Central to modernise its email infrastructure and remove a critical blocker to achieving Cyber Essentials Plus certification.
The project involved migrating from an end-of-life Exchange 2016 environment to Exchange Server Subscription Edition (SE), ensuring compliance requirements were met while maintaining continuity across the organisation.
Client Background
Calico Homes is a leading social housing provider based in Burnley, managing more than 5,000 homes across the town and surrounding area.
They provide housing for people who need it most, including families, people who live alone, older people, and those at risk.
The Challenge
Calico was working towards Cyber Essentials Plus certification when a critical issue was identified within its existing email infrastructure.
The organisation was still running an end-of-life Exchange 2016 server which had become a blocker to compliance. Microsoft support for Exchange 2016 had already ended in October 2025, creating both security and operational risks. Alongside this, an expired Federation Delegation Certificate was causing further issues within the hybrid Microsoft 365 environment.
There was also increasing pressure around timescales. Coexistence support between Exchange 2016 and the newer Exchange Server Subscription Edition (SE) would only remain supported until mid-2026, meaning action was required quickly.
The Solution
Central has a long-standing relationship with Calico, built on trust and a deep understanding of how the organisation operates. When the compliance deadline began to bite, that familiarity made Central the natural choice.
Working closely with Calico’s internal IT team, Central planned and delivered a complete Exchange modernisation project, providing rapid-response support and clear communication throughout to ensure compliance deadlines could be met.
The project included:
- Deploying a brand-new Exchange Server Subscription Edition (SE) environment on Windows Server 2022
- Migrating all system and arbitration mailboxes from the legacy Exchange 2016 server
- Rebuilding the Exchange Federation certificate from scratch, as an expired certificate cannot be renewed and must be fully recreated
- Recreating SMTP relay connectors and updating all dependent applications, scanners and multifunctional devices
- Updating Autodiscover and hybrid Microsoft 365 configuration settings
- Coordinating DNS updates (internal and external) to redirect traffic
- Working with Calico IT to update ForcePoint mail filtering configuration
- Monitoring the legacy Exchange server in a powered-off state before full decommissioning
- Fully uninstalling Exchange 2016 and removing associated DNS records
The Outcome
The migration was completed successfully and with minimal impact on day-to-day operations.
As a result:
- Exchange 2016 was fully decommissioned, removing the Cyber Essentials Plus blocker
- Hybrid Microsoft 365 connectivity was maintained throughout the project
- SMTP relay services continued without disruption to business-critical systems and devices
- Calico now benefits from a modern, fully supported Exchange environment ready for future Microsoft requirements
- Most importantly, Calico successfully achieved Cyber Essentials Plus certification
Feedback
Following completion of the project, Calico’s Head of IT shared the following feedback with the Central team:
“I just wanted to thank you for all of the very last minute emergency support and work you did for us regarding the old Exchange implementation and getting the Exchange SE in and live… but as I said I just wanted to let you know we got it and extend my thanks.”
