Exchange Server Version

            string exchangeVersion = "";
            exchangeVersion = OwaTools.GetExchangeServerVersion("foo.bar@outlook.com", "pwd", "https://outlook.office365.com/EWS/Exchange.asmx");


using Microsoft.Exchange.WebServices.Data;


        /// <summary>
        /// gets Exchange Server Version
        /// </summary>
        /// <param name="userName">Domain\Username or email adress in some cases (office365)</param>
        /// <param name="userPassword">pwd</param>
        /// <param name="uri">https://server/EWS/EWS/Exchange.asmx e.g. https://outlook.office365.com/EWS/Exchange.asmx  </param>
        /// <returns></returns>
        public static string GetExchangeServerVersion(string userName, string userPassword, string uri)
        {
            var service = new ExchangeService(ExchangeVersion.Exchange2007_SP1);
            service.Credentials = new NetworkCredential(userName, userPassword);
            service.Url = new Uri(uri);
            ServicePointManager.ServerCertificateValidationCallback = (sender, certificate, chain, sslPolicyErrors) => true; // ignore invalid or self signed certificates
            var inbox = Folder.Bind(service, WellKnownFolderName.Contacts);
            var esi = inbox.Service.ServerInfo;
            return esi.VersionString;
        }