1. Add SFTP backup and merge functions for session information.
   》》8 kinds of high-strength encryption algorithms are provided for users to choose freely, reducing the risk of database files being cracked violently.
   》》Multiple merge modes are available.
2. Fix the problem that the terminal is not synchronized with the SFTP directory under the Ubuntu system.
3. After SSH is disconnected, add whether to restore to the directory before SSH is disconnected when reconnecting.