System Requirements
| OS (64Bit) | Windows Server 2016 Windows Server 2019 Windows Server 2022 Windows Server 2025 |
| Hardware | Processor: minimum dual core RAM: minimum 4GB |
| Software | NET Framework 4.8.0 or later Windows PowerShell 5.1 and ExchangeOnlineManagement PowerShell module version 3.6 or later for Exchange Online PowerShell V3 |
| Recommendations | Exchange On-Premises: We recommend to install contactSync on a member server within the domain (e.g., dedicated contactSync server or file server). The machine should be uncritical (e.g., may be restarted without complications). The contactSync server must have a high bandwidth connection to the DC/GC. Exchange Online: See recommendations for on-premises; but you can use also a standalone computer. |
| Supported Exchange Versions* | Exchange 2013* SP1 and later Exchange 2016* and later Exchange 2019* and later Microsoft 365 Exchange Online |
* Microsoft will be stopping support for Exchange 2026 and Exchange 2019 on the 14th October 2025.
Microsoft stopped supporting Exchange 2013 on the 11th April 2023.
Microsoft stopped supporting for Windows Server 2012 and Windows Server 2012 R2 on the 10th October 2023.
As much as we would like to keep up compatibility for all versions, we cannot support an Environment, which is no longer supported by the manufacturer.
Microsoft will start blocking EWS requests to Exchange Online on 1st October 2026.
https://techcommunity.microsoft.com/blog/exchange/retirement-of-exchange-web-services-in-exchange-online/3924440