PowerTCP SSH and SFTP for .NET 4.9 has been released with new features: 

• Support for multiple concurrent transfers.
• Support for SSH compression.
• Support for the diffie-hellman-group-exchange-sha256 KEX algorithm.
• Up to a 50% increase in transfer speed.

 For a complete list of improvements, see the PowerTCP SSH and SFTP for .NET Release History.