Enterprises still hosting on-premises Exchange mail, its time to face reality: Microsoft will soon no longer support your infrastructure.Earlier this week, the tech giant released its final roll-up patch for Exchange Server 2019 (Cumulative Update 15). On October 14, Microsoft will officially stop supporting both Exchange Server 2016 and Exchange Server 2019 meaning no more updates, technical help, bug fixes, or security patches.With end of life (EOL) pending, Microsoft customers must now either move to the fully-hosted Exchange Online or Microsoft 365, or pay for on premises Exchange Server Subscription Edition (SE) licenses to receive continued support and updates.Every software company out there Microsoft, Oracle are all trying to nudge gently, and sometimes not so gently, their customer base to the cloud, said Matt Kimball, a principal data center analyst with Moor Insights & Strategy. Theyre doing everything but forcing companies to move to cloud-based or SaaS-based models.Upgrade to Exchange Server SE, or stay out of date at your own riskMicrosoft will roll out Exchange Server SE early in the second half of 2025, and release the first CU for the platform later in the year. Once that happens, all other versions of Exchange Server will be out of support.Its not unexpected. Adam Preset, VP analyst at Gartner, pointed out that there have been 10 versions of Exchange Server since 1996. This is just what happens, he said.The final cumulative update for Exchange 2019 integrates all prior security patches and introduces server-side components for Feature Flighting, an optional cloud-based service that allows for immediate updating once new features are available, he said. This will help ensure stability and security up to the EOL date.Post-EOL, organizations can operate existing installations at their own risk, he said. Email is an essential and business critical workload, though, so staying on Exchange Server 2019 is unwise.To install Exchange Server SE CU1 (or later), organizations will have to first decommission and remove all older versions of Exchange, according to Microsoft. Organizations have two options when moving to the new subscription model: A legacy upgrade (introducing new servers and uninstalling old servers); or (only for 2019) an in-place upgrade (downloading and installing the latest upgrade package).In addition to purchasing required licenses, customers must also maintain an active Microsoft subscription, which means purchasing either cloud subscription licenses for all users and devices, or buying Exchange Server SE licenses with software assurance (SA).Preset pointed out that theres no substitute for checking on licensing agreements and consulting with Microsoft if an organization needs to transition to Exchange Server SE. Also, the new model will accept Exchange 2019 product keys to help simplify the upgrade process.Its time for enterprises to embrace the futureTo some, on-prem email hosting in 2025 seems like a quaint notion.Who the heck is still running Exchange on premises?, Kimball asked. I say that jokingly but I kind of mean it too.Cloud computing has grown massively over the last 15 years, and email has been typically one of the first candidates to be moved up into the cloud, he noted.Outside of super-high privacy reasons, I cant see the efficiency of running on-premises, said Kimball. However, he noted, theres always going to be a laggard customer base that is slow to adopt not even new technology, but current technology.These corner cases typically have unique privacy or regulatory requirements or it might simply come down to company culture. That points to something bigger: Youre hosting your own email and managing it a certain way because youve always done it that way, said Kimball.But thats typically not best for a business users and partners, not to mention its IT staff, who want to be doing more exciting and challenging kinds of work. Enterprises should be focused on staying current, quickly gaining access to the latest capabilities (in Microsofts case, think access to Copilot) and the absolute resiliency of the cloud, said Kimball.However, he did question Microsofts rather abrupt end-of-service for Exchange Server 2019. In other cases, even after EOL, Microsoft has been known to continue to support legacy infrastructures. Five years is not a long time to have a product in the market, said Kimball. End of support is a big thing.Important migration strategiesAnalysts emphasize that organizations on Exchange 2019 must build a strategy for migration, performing extensive planning and assessing infrastructure for a seamless transition.The first thing to do, Kimball said: Perform a cost-benefit analysis or ROI study that takes into account all direct and indirect costs, infrastructure, software, people costs, financial impact of downtime and what valuable IT staff have to do to maintain legacy environments day after day after day, the care and feeding. Then compare that to moving to hosted Exchange.Unless theres a real hard and fast regulatory requirement, I would be willing to wager that the cost benefit analysis is going to lead to a migration to the cloud, Kimball noted.Overall, enterprises, whether Microsoft customers or not, should consider migrating to the cloud when on-premises maintenance costs rise, advanced security features are required, or they want more (and better) cloud integration, said Preset.Meticulous planning is essential to ensure a smooth transition, he said.To reduce the risks of disruption when migrating, Preset suggested having IT personnel skilled in Exchange and cloud technologies, project managers, and support from vendors with migration experience. Enterprises also need to allocate budget for new licenses, potential third-party migration tools, training expenses for IT staff, and new systems.However, Preset emphasized, if you know you need to transition to cloud anyway, Microsoft is not the only game in town. If youre ready for a bigger change, it might be time to look at alternatives such as Google Workspace or other vendors with email services.