As discussed in a previous post, Dynamics 365 version 9 uses TLS 1.2 as its security protocol. This is enabled by default in the Microsoft .NET Framework 4.6+, and it is supported and optional in .NET 4.5+.
The Unified Service Desk client application uses the following .NET versions:
- Unified Service Desk 3.1 or higher version – Microsoft .NET Framework 4.6.2
- Unified Service Desk 3.0 version – Microsoft .NET Framework 4.5.2
In order to support TLS 1.2 in the Unified Service Desk client, you will have the following options:
- Install USD 3.1 or higher. When doing so, it will default to using TLS 1.2
- If using USD 3.0 or lower, perform a registry setting update as discussed here
If you do update to USD 3.1 or higher, you will need to ensure any custom hosted controls are also using .NET 4.6+.