TightVNC full changelog

Server for Windows: Fixed a black screen and loss of remote control when a User Account Control (UAC) prompt appeared with the "Connect to RDP session" option enabled.
Server for Windows: Fixed the Attach Listening Viewer dialog failing to appear when opened from the tray icon.
Viewer for Windows: Fixed connection history becoming empty or failing to save changes when application settings or the history contained unknown options, such as those added by another TightVNC version.
Viewer for Windows: Fixed unintended saving of application settings when connecting to a server or changing connection options. Application settings and connection history are now saved independently.
Viewer for Windows: Showing or hiding the toolbar now affects only the current connection window, leaving the default for new windows unchanged.
Viewer for Windows: Fixed removal of tab characters from connection addresses.
Server for Windows: Improved diagnostic logging for startup failures, desktop changes and failures in log collection.
Server and Viewer for Windows: Fixed several minor issues affecting stability and error handling.
Server and Viewer for Windows: About dialogs now display the third component of the version number.
Installer for Windows: Added CHANGELOG.txt to all installation packages, making release notes available in the installation directory.

First release in the TightVNC 4 series. The base version is free to use for personal and commercial purposes, with no expiration. An optional paid TightVNC Pro subscription adds full session encryption.
Server and Viewer for Windows: Added SRP-6a password authentication with support for long passwords and international characters. The new method protects authentication without sending the password over the network and is included in the free version.
Server for Windows: Redesigned local security around Windows accounts and permissions. Administrative operations require appropriate privileges, replacing the separate administrative password used in TightVNC 2. Service settings, credentials, and event records use protected storage.
Server for Windows: Introduced Server Overview and dedicated Control Centers for service and application modes. Redesigned configuration dialogs simplify authentication, encryption, access control, and administration.
Server and Viewer for Windows: Added TLS 1.3 session encryption with TightVNC Pro, protecting screen updates, input, clipboard contents, and file transfers. Pro authorization is required on both computers.
License Manager for Windows: Added a dedicated application for installing Pro licenses and viewing their status. Pro is activated within the same TightVNC installation, without a separate download.
Installer: Added migration of supported Server settings, Viewer settings and connection history, and existing VNC passwords from TightVNC 2. Traditional VNC authentication remains available for compatibility. Set new passwords to use the new authentication method. Installing TightVNC 4 replaces TightVNC 2; side-by-side installation is not supported.

Viewer for Windows: Fixed a potential buffer overrun when processing invalid Tight-encoded screen data. The Viewer now validates decompressed data sizes and rejects empty compressed blocks before converting or drawing pixels.

Viewer for Windows: Added checks for oversized framebuffers, RichCursor updates, and Tight JPEG rectangles before allocating or decoding pixel data, preventing integer overflows and unsafe memory access when processing invalid data from a server.
Viewer for Windows: Improved error messages when the server does not offer a compatible authentication method.

Server for Windows: Fixed operation in application mode for environments with multiple simultaneous RDP sessions (bug #1647).
Server for Windows: Increased maximum screen size (width or height) from 32,000 to 65,535 pixels.
Server and Viewer for Windows: Fixed bugs in buffer size calculation when receiving and converting clipboard data.
Installer for Windows: The uninstaller now correctly removes the TightVNC Service Control Application.

Server for Windows: Fixed connection issues in Windows XP that were introduced by the previous version.

Server for Windows: Support for the third-party ExtendedDesktopSize pseudo-encoding has been removed due to incompatibility issues, complexity, and error-proneness. It has been replaced with a similar TightVNC-specific protocol extension, the new DesktopConfiguration pseudo-encoding, which allows users to choose a specific monitor in the viewer when a remote host has multiple monitors connected. Multi-monitor handling will be implemented in next versions of MightyViewer and Remote Ripple.
Server for Windows: Fixed an issue with disabled file transfers in RDP connections.