MailKit

• Fixed ImapFolder.AddFlags() to throw FolderNotOpenException if the folder is not opened in read-write mode. (issue #202)
• Fixed ImapFolder.GetMessage/BodyPart/Stream() to not modify a dictionary while looping over it. (issue #201)
• Fixed ImapFolder to throw FolderNotFoundException instead of ArgumentException when the command fails due to the folder not existing.

• Added ImapClient.GetFolders(FolderNamespace, ...) to allow getting the full (recursive) list of folders for a particular namespace.
• Added a FolderAttributes.Inbox flag that gets set on the Inbox folder.
• Fixed the IMAP code to properly treat the INBOX folder name case-insensitively.
• Added ServiceNotConnectedException, ServiceNotAuthenticatedException, and FolderNotOpenException as a more specific errors than InvalidOperationException. (Note: they all subclass InvalidOperationException so old code continues to work).
• Added Pop3Client.GetStream() to allow fetching messages or headers as an unparsed stream. (issue #198)
• Fixed usage of Socket.Poll() to not loop 1000 times per second.
• Added more ImapFolder.GetStream() overloads.
• Added ImapFolder.CreateStream() and CommitStream() protected methods which are meant for subclasses that intend to implement caching.

• Added hooks to allow subclassing ImapFolder.

• Added new ImapFolder.GetStream() overloads that allow fetching only the TEXT stream.
• Fixed ImapFolder.Search() to always treat the search results as UIDs even when the server (such as AOL) does not include the required UID tag in the ESEARCH response. (issue #191)
• Fixed ImapClient to set the engine.Uri even for Windows81 profiles (fixes a NullReferenceException for the various Windows81 profiles). (issue #192)
• Work around a GMail bug where it does not quote flags containing []'s. (issue #193)
• Fixed the IMAP code to accept GMail label names that start with a '+'. (issue #195)
• Delay throwing ProtocolException due to an unexpected disconnect when reading responses to PIPELINE'd SMTP commands in case one of the responses to those commands contains an error code that might hint at why the server disconnected. (issue #194)

• Fixed a STARTTLS regression in SmtpClient that was introduced in 1.0.15. (issue #187)

• Modified the Pop3Client to immediately query for the message count once the client is authenticated. This allows the Pop3Client to now have a Count property that replaces the need for calling GetMessageCount(). (issue #184)

• Added SearchQuery.HeaderContains() and obsoleted SearchQuery.Header() for API consistency.
• Added workaround for GMail's broken FETCH command parser that does not accept aliases. (issue #183)

• Added a ServerCertificateValidationCallback property to all clients so that it is not necessary to set the global System.Net.ServicePointManager.ServerCertificateValidationCallback property.
• Fixed MailService.Connect(Uri) to properly handle Uri's with Port value that had not been explicitly set. (issue #170)
• Added logic to properly handle MODSEQ-based search responses. (issue [#166 and issue #173](https://github.com/jstedfast/MailKit/issues/166 and issue #173))
• When an ImapClient gets disconnected, if an ImapFolder was in an opened state, update its state to closed to prevent confusion once the ImapClient is reconnected.
• Fixed a bug in Pop3Client.Authenticate() for servers that just reply with "+OK\r\n" to the SASL challenge. (issue #171)
• Clear the POP3 capability flags if the POP3 server responds with -ERR at any time. Some servers will reply with a list of capabilities until the client is authenticated, and then reply with -ERR meaning that the client should not attempt to use previously listed capabilities. (issue #174)

• Added a FileName convenience property to BodyPartBasic which works the same way as the MimeKit.MimePart.FileName property.
• Added a MessageSummaryFetched event to IMailFolder to better enable developers to both provide progress feedback to their users as well as enable them to better recover from exceptions (such as a dropped connection) occurring during the fetching of message summaries.
• Added support for the IMAP SORT=DISPLAY extension.
• Added a work-around for Cyrus IMAP 2.4.16 sending untagged SEARCH responses when untagged ESEARCH responses are expected.

• Fixed ImapFolder.GetMessage(), GetBodyPart() and GetStream() to throw an ImapCommandException rather than returning null if the server did not response with the message data.
• Added new, much more usable, Connect() methods to ImapClient, Pop3Client, and SmtpClient that take a hostname, port, and SecureSocketOptions.
• Added a workaround for smtp.strato.de's blatant disregard for standards. (issue #162)
• Fixed ImapFolder.Close() to require ReadWrite access if expunge is true.
• Fixed IMAP SORT queries to inject "RETURN" before the orderBy param. (issue #164)
• Implemented support for the IMAP ACL extension.

• Make sure that the IMAP stream supports timeouts before using them (fixes a regression introduced in 1.0.10).
• Added BodyParts and Attachments convenience properties to MessageSummary.
• Added TextBody and HtmlBody convenience properties to MessageSummary.
• Added ImapClient.IsAuthenticated, Pop3Client.IsAuthenticated and SmtpClient.IsAuthenticated properties.
• Changed the ImapClient.Inbox property to throw InvalidOperationException if you try to access it before authenticating instead of returning null.
• Added an ImapClient.IsIdle property to check if the ImapClient is currently in the IDLE state.

• Added support for the IMAP ID extension.

• Modified UniqueId to contain a Validity value. This allows ImapFolder.Append(), CopyTo(), and MoveTo() to provide the caller with a way to make sure that the UIDs are (still) valid in the destination folder at a future point in time.
• Modified ImapFolder.UidValidity to be a uint instead of a UniqueId which not only makes more sense but also simplifies comparison.
• Fixed GMail Label APIs to use the modified UTF-7 encoding logic meant for folder names as it appears that GMail wants label names to be encoded in this way. (issue #154)

• Fixed the SMTP BINARYMIME extension support to work properly. (issue #151)
• Fixed ImapFolder.Open() to not set the PermanentFlags to None if another folder was open (preventing SetFlags/AddFlags/RemoveFlags from functioning properly). (issue #153)

• Marked Pop3Client methods that take UIDs as [Obsolete]. It is suggested that the equivalent methods that take indexes be used instead and that UID-to-index mapping is done by the developer. This takes the burden off of the Pop3Client to maintain a mapping of UIDs to indexes that it cannot easily maintain.
• Fixed SmtpCommandException to only serialize the Mailbox property when it is non-null. (issue #148)
• Fixed IMAP support to accept a UIDVALIDITY value of 0 (even though it is technically illegal) to work around a bug in SmarterMail 13.0. (issue #150)
• Fixed ImapFolder.GetSubfolders() to filter out non-child folders from the list that it returns (once again, a work-around for a SmarterMail 13.0 bug). (issue #149)

• Fixed some issues revealed by source analysis.
• Migrated the iOS assemblies to Xamarin.iOS Unified API for 64-bit support.

Note: If you are not yet ready to port your iOS application to the Unified API, you will need to stick with the 1.0.5 release. The Classic MonoTouch API is no longer supported.

• Added Connect() overloads which takes a Socket argument (issue #128).
• Added support for SMTP Delivery Status Notifications (issue #136).
• Modified the ImapFolder logic such that if the IMAP server does not send a PERMANENTFLAGS resp-code when SELECTing the folder, then it will assume that all flags are permanent (issue #140).

• Modified the IMAP BODYSTRUCTURE parser to allow NIL tokens for Content-Type and Content-Disposition parameter values. (issue #124)
• Added ImapFolder.GetBodyPart() overrides to allow fetching body parts based on a part specifier string. (issue #130)

• Added a new ImapFolder.Fetch() overload that takes a HashSet<string> of header fields to fetch instead of a HashSet<HeaderId> for developers that need the ability to request custom headers not defined in the HeaderId enum.
• Added an SmtpClient.MessageSent event and an OnMessageSent() method that can be overridden.

• Modified ProtocolLogger to flush the stream at the end of each Log().
• Fixed IMAP SEARCH queries with empty string arguments.
• Fixed the IMAP FETCH parser to accept qstrings and literals for header field names.
• Improved documentation.

• Fixed Pop3Client.GetMessages (int startIndex, int count, ...) to use 1-based sequence numbers.
• Fixed POP3 PIPELINING support to work as intended (issue #114).
• Added a work-around for Office365.com IMAP to avoid ImapProtocolExceptions about unexpected '[' tokens when moving or copying messages between folders (issue #115).
• Disabled SSLv3 for security reasons (POODLE), opting instead to use TLS.