File Server: Added support for SFTP v5 which improves compatibility with WinSCP client, this requires SFTP v5 to enable File Hashing extension that makes it possible to calculate checksums of remote files.
File System: MountCapableFileSystemProvider's FileSystemNotifier now raises GetAttributesPreview, GetAttributesSurrogate and GetAttributesCompleted events for mounted directories.
Mail: Added MsgMessageException exception class (represents errors related to Microsoft Outlook MSG format).
Mail: Improved handling of invalid SMTP addresses in MSG parser.
IMAP: Improved error handling when parsing IMAP envelope fields.
TLS Core: Added SslSettings.SetPreferredSuites/GetPreferredSuites methods to make it possible to specify client-side TLS cipher preference.
TLS Core: Improved logging when remote party does not support TLS 1.3.
TLS Core: Optimized TlsSocket.Negotiate method when TLS 1.3 is enabled but not supported by the remote side.
Cryptography: Added support for private keys using PBKDF2 with HMAC/SHA-2 (RFC 8018 / PKCS #5 v2.1).
Cryptography: Optimized creation of algorithm objects in CNG layer.