PrimalDesk Windows Server builds, IddCx requirements and current display limitations.
The current PrimalDesk host targets Windows Server with Desktop Experience. Its remote display driver needs IddCx 1.4 or newer. Microsoft lists the following base builds and bundled IddCx versions:
| Windows Server release | Base build | IddCx | PrimalDesk host position |
|---|---|---|---|
| Server 2019 | 17763 | 1.3 | Below the required remote-display driver API; not supported. |
| Server 1909 | 18363 | 1.4 | First Server release with the required API, but not a supported current deployment target. |
| Server 20H2 | 19042 | 1.5 | Meets the driver API floor, but not a supported current deployment target. |
| Server 2022 | 20348 | 1.7 | Supported baseline. |
| Server 2025 | 26100 | Check the installed IddCx runtime and driver/GPU path on the actual machine; supported target for SDR sessions. |
Microsoft’s IddCx version table names the Server 2019–2022 versions above. Its current Server table does not list Server 2025, so the 2025 row does not assert an unverified IddCx number. Microsoft’s release information identifies Server 2025 as build 26100.
HDR status
IddCx 1.10 introduces the Windows indirect-display APIs needed for HDR10 and wide color. Microsoft documents those APIs on Windows 11 23H2 and the September 2023 update to 22H2. This is an OS capability threshold, not a claim that PrimalDesk can currently deliver HDR on any Server version. The present PrimalDesk remote-display driver deliberately reports SDR-only capability; HDR end-to-end support is not yet enabled. Selecting an HDR-capable GPU or a newer Server build does not change that.
Use an up-to-date x64 installation with Desktop Experience, functioning Remote Desktop Services and current GPU drivers. A virtual machine must expose an encoder-capable GPU to the host. Test your intended applications with one user before scaling to several sessions.
Desktop editions of Windows may work in some configurations, but are outside the supported multi-user host deployment path. Your Windows licensing, Remote Desktop Services configuration and GPU capabilities remain independent requirements.