Synergy 1

v1.21.0-beta (June 18, 2026)

Security

• CVE-2021-42072: Closed a gap where the server did not sufficiently verify connecting clients, which allowed an unauthorised computer on the network to connect.
• CVE-2021-42073: Prevented an attacker from entering an active session by supplying a client name matching a configured computer, which would have given them input and clipboard access.
• CVE-2021-42074: Fixed a race in TLS connection handling that could crash the server and disconnect every computer.
• CVE-2021-42075: Corrected file descriptors not being closed for established connections, which a remote attacker could exhaust.
• CVE-2021-42076: Stopped over-long messages from exhausting server memory.

Features

• Clients can now be given several server addresses and will work through the list until one connects, improving reliability on changing or multi-network setups.
• Replaced the unreliable scroll speed setting with a new scroll scaling control that gives smoother, more predictable scrolling between computers.
• Added a dedicated client configuration dialog that gathers the client-side options into one place instead of scattering them across the interface.
• Introduced an option to start already locked to the current computer, so input stays put until you choose to switch.
• Built a simple search into the log view so you can find specific entries without scrolling through everything.
• A new option can show the version number in the window title bar, making it easier to confirm which build is running.
• Added translations for Korean, English, Spanish, Italian, Japanese, Korean, Russian, and Chinese (Simplified).

Enhancements

• Fragile log parsing replaced with more robust IPC between Core and GUI.
• Existing settings are carried across automatically when upgrading, so saved screen layouts and preferences are kept without reconfiguring.
• The suggested server address is now more accurate and updates on its own as your network connection changes.
• Connection error dialogs no longer appear while the window is hidden, keeping background running quiet.
• Wording throughout the interface now refers to a "Computer" rather than a "Screen" to better match how the layout works.

Bug fixes

• Made the back and forward mouse buttons work again on all platforms.
• Corrected key repeat so a held key repeats as expected instead of registering as separate press and release events.
• Recovered clipboard sharing that had stopped working, and resolved a related crash affecting it.
• Stopped the application from crashing when a hotkey was not delivered to every connected computer.
• Eliminated a possible crash the first time the background service started on Windows.
• Repaired wrong character output on macOS when using the RIME input method.
• Ensured the tray icon appears on macOS when the colourful icon style is selected.
• Allowed commas and semicolons to be used within hotkey definitions, which previously could not be saved.