Each release of EWSEditor includes the distribution of the EWS Managed API it was built for. EWSEditor uses .NET Framework version 4.5.1 which can be downloaded here: .NET Framework 4.5.1. The project is under Visual Studio 2013. This version of EwsEditor uses EWS Managed API built from GIT. The EWS Managed API requires a minimal of .NET 3.5. A copy of the 2.2 version of the EWS managed API is included in case you wish to use it instead of the version built from GIT.
EWS Managed API… open source? YES! It’s now Open Source!!! https://blogs.msdn.microsoft.com/webdav_101/2014/09/29/ews-managed-api-open-source-yes-its-now-open-source/