The binary distribution of apns-sharp is not strongly named, so it's not possible to directly reference from a strongly named assembly.

Would it be possible to sign the binary distribution?

C:\Temp\Apns-Sharp-1.0.3.0>sn -v JdSoft.Apns.Notifications.dll

Microsoft (R) .NET Framework Strong Name Utility Version 4.0.30319.1 Copyright (c) Microsoft Corporation. All rights reserved.

JdSoft.Apns.Notifications.dll does not represent a strongly named assembly

You can download the source and sign it yourself, naturally.

I'll consider signing it in the next release though too.