MailKit 2.10.0

* Don't enable support for TLS v1.1 by default anymore. (issue #1077) * Added support for the SCRAM-SHA-512 SASL mechanism. (issue #1097) * Added support for the OAUTHBEARER SASL mechanism. * Updated SSL certificate info for the common mail servers (GMail, outlook.com, Yahoo! Mail, etc). * Improved the SslHandshakeException error message to report common mistakes like trying to initiate an SSL connection on a non-SSL port. * Improved IMAP's "Unexpected token" exception messages a bit * Updated code to use ArrayPools from System.Buffers. API Changes Since 2.0.x: * Obsoleted SearchQuery.HasCustomFlags() and SearchQuery.DoesNotHaveCustomFlags(). These are now SearchQuery.HasKeywords() and SearchQuery.NotKeywords(), respectively. * Obsoleted SearchQuery.DoesNotHaveFlags() in favor of SearchQuery.NotFlags(). * Obsoleted the IMessageSummary.UserFlags property in favor of IMessageSummary.Keywords. * Obsoleted the MessageFlagsChangedEventArgs.UserFlags property in favor of MessageFlagsChangedEventArgs.Keywords. * All IMailFolder.Fetch and IMailFolder.FetchAsync methods that took a HashSet<string> userFlags argument now take an IEnumerable<string> keywords argument. Note: this only affects you if your code used named method parameters (e.g. userFlags: myUserFlags). Note to users upgrading from MailKit 1.x: In order to authenticate using the XOAUTH2 SASL mechanism, you must now use the following approach: client.Authenticate (new SaslMechanismOAuth2 (username, auth_token));