You can use the Client Login Extension with the following .NET Framework versions:
.NET 2.0
.NET 3.5
NOTE:ClientLoginExtensionConfigurationUtilitySetup.msi bundles Client Login Extension Configuration Utility.exe and IdentityManagerClientLoginExtension_en.msi. IdentityManagerClientLoginExtension_en.msi does not have any dependency on .NET framework whereas Client Login Extension Configuration Utility.exe file is dependent on the .NET 3.5 framework for its operation.