Hi,
Rebex Security, Rebex Time and Rebex ZIP support .NET Standard 2.1 on .NET Core 3.1 (on Windows, Linux and macOS), and .NET Standard 2.0 on .NET Core 3.1, 2.1, on Xamarin.iOS 12.3 (or higher), on Xamarin.Android 9.1 (or higher) and on Mono 5.14 (or higher). Support for .NET Standard 2.0 on Universal Windows Platform (build 16299 or higher) and Xamarin.Mac (version 3.8 or higher) is experimental.