An upgrade of Windows’ Active Directory is required to improve the support of cloud services. This concerns an upgrade to domain level 2012 R2. Only new functionality will be added, so we do not expect any impact on linked systems.

During the necessary server reboot authenticating with the AD is not possible for a maximum of 15 minutes. This applies to a wide range of services, like logging on from a workstation or in your mail. Existing sessions are generally not interrupted.