I'm helping a large workplace that has several buildings and roughly 3,000 employees move away from Microsoft Exchange Server 2019/SE. The environment is isolated from the public internet, so any replacement needs to run on-premises and support offline operation.
Email itself is not the main problem. The difficult part is replacing Exchange's workplace-management features, especially shared calendars, room booking, and resource booking. The organisation has many service vehicles and other resources that engineers need to reserve for emergency field work.
The office suite is already being evaluated separately, with a few users likely retaining Excel because there is not yet a suitable replacement. For Exchange, though, I have not found one product that provides comparable email, calendar, room, and resource-management capabilities in a disconnected environment.
Are there any realistic all-in-one alternatives, or is the practical solution to combine an on-premises mail server with separate calendar and booking systems?
4 Answers
Zimbra is worth evaluating as a traditional on-premises groupware option. OpenDesk may also cover some of the collaboration and calendar requirements, although you should verify its resource-booking workflow against the organisation’s vehicle and room needs. In practice, Exchange-level coverage may still require more than one product.
Nextcloud is a reasonable candidate for the calendar, shared scheduling, and resource-booking side when hosted internally. It may not replace every Exchange feature, so pairing it with a separate on-premises mail platform could be the more realistic architecture rather than searching for one perfect replacement.
If the system is completely disconnected, continuing with Exchange may still be the least disruptive short-term option, provided licensing and support remain acceptable. The replacement decision is being driven by future availability, potential cost increases, and a desire to reduce dependence on US software, so the organisation should compare the long-term operational cost of a multi-product setup against retaining Exchange temporarily.
Those are exactly the concerns behind the search. Exchange may continue to work for a while, but the organisation does not want to wait until support or licensing forces an emergency migration.
Take a look at grommunio. It is designed as an on-premises groupware platform and may provide a closer fit for organisations that still need mail, calendars, and collaboration without relying on external cloud services. IceWarp is another option to investigate, although its pricing may make it unsuitable at this scale.
That is one of the combinations being considered. The final product choices are handled by different teams, but the lack of a complete replacement is why a split solution is becoming likely.