Is Combü Windows 10 Universal compliant?

I wanted to use Windows 10 Store IAP together with Combü in the same project. While everything works fine building for Windows Standalone I'm facing a lot of errors when building for Windows 10 Universal. Most errors seem to point to the Combü asset so I'm wondering if it is even complaint with Windows 10 Universal at all?

Here are the errors:

AssetsCombuScriptsCombuManager.cs(128,64): error CS1061: 'DateTime' does not contain a definition for 'ToShortTimeString' and no extension method 'ToShortTimeString' accepting a first argument of type 'DateTime' could be found (are you missing a using directive or an assembly reference?)

AssetsCombuScriptsCombuManager.cs(128,31): error CS1061: 'DateTime' does not contain a definition for 'ToShortDateString' and no extension method 'ToShortDateString' accepting a first argument of type 'DateTime' could be found (are you missing a using directive or an assembly reference?)

AssetsCombuScriptsCombuManager.cs(389,67): error CS0117: 'ASCIIEncoding' does not contain a definition for 'Default'

AssetsCombuScriptsCombuManager.cs(560,34): error CS0234: The type or namespace name 'SHA1' does not exist in the namespace 'System.Security.Cryptography' (are you missing an assembly reference?)

AssetsCombuScriptsCombuManager.cs(560,82): error CS0234: The type or namespace name 'SHA1CryptoServiceProvider' does not exist in the namespace 'System.Security.Cryptography' (are you missing an assembly reference?)

AssetsCombuScriptsMiniJSON.cs(634,29): error CS1061: 'Type' does not contain a definition for 'IsPrimitive' and no extension method 'IsPrimitive' accepting a first argument of type 'Type' could be found (are you missing a using directive or an assembly reference?)

These errors are of course preventing the project for building (and therefor testing).