The project to convert mIRC to Unicode has taken almost two years of development and testing and has required tens of thousands of changes to 150,000+ lines of source code. This has been the most complex and time-consuming update to mIRC since it was created in 1995, when it started out as a non-Unicode, 16-bit, Windows 3.1 application.
Many areas of mIRC have had to be updated or re-written, from file handling to text processing, from display to memory allocation, from server communications to file transfers.
mIRC should now be faster, more stable, and more compatible with the latest versions of Windows, and should be able to better handle the display and input of a variety of languages.
In addition to being converted to Unicode, there are a few other notable changes:

• Improved Windows 7 compatibility
• More reliable INI file handling
• Faster text display/scrolling
• Speech support
• Improved interface design for a number of features
• Automatic text color correction
• Menubar ALT key show/hide feature
• Support for italic text and other font styles
• Optimized SSL routines
• Status window SSL connection icon
• IPv6 support
• Improved portable support
• Persistent channel history
• Digitally signed executables
• Automatic splitting of long channel/private messages
• Full screen display with F11 function key
• UPnP support
• Many bug fixes
• And more