Features :
• Generates self-contained executable installers
• Support for ZLib, BZip2 and LZMA data compression (files can be compressed individually or together)
• Uninstall support (installer can generate an uninstaller)
• Customizable user interface (dialogs, fonts, backgrounds, icons, text, checkmarks, images etc.)
• Classic and Modern wizard interface
• Fully multilingual, support for multiple languages (including RTL langauges) in one installer. More than 40 translations are already available, but you can also create your own.
• Page system: You can add standard wizard pages or custom pages
• User selection of installation components, tree for component selection
• Multiple install configurations (usually Minimal, Typical, Full), and custom configuration
• Installer self-verification using a CRC32 checksum
• Small overhead over compressed data size (34 KB with default options)
• Ability to display a license agreement in text or RTF format
• Ability to detect destination directory from the registry
• Easy to use plug-in system (lots of plug-ins for creation of custom dialogs, internet connections, HTTP downloading, file patching, Win32 API calls, etc. are included)
• Installers can be as large as 2GB
• Optional silent mode for automated installations
• A preprocessor with support for defined symbols, macros, conditional compilation, standard predefines
• A lovely coding experience with elements of PHP and assembly (includes user variables, a stack, real flow control, etc.)
• Installers have their own VMs that let you write code that can support:
o File extraction (with configurable overwrite parameters)
o File/directory copying, renaming, deletion, searching
o Plug-in DLL calling
o DLL/ActiveX control registration/unregistration
o Executable execution (shell execute and wait options)
o Shortcut creation
o Registry key reading/setting/enumerating/deleting
o INI file reading/writing
o Generic text file reading/writing
o Powerful string and integer manipulation
o Window finding based on class name or title
o User interface manipulation (font/text setting)
o Window message sending
o User interaction with message boxes or custom pages
o Branching, comparisons, etc.
o Error checking
o Reboot support, including delete or rename on reboot
o Installer behavior commands (such as show/hide/wait/etc.)
o User functions in script
o Callback functions for user actions

Changes in version 2.39:
Major Changes:
* Added !define /file and !searchparse (patch #2016254)
* Added service pack macros (AtLeastServicePack, IsServicePack, AtMostServicePack) for WinVer.nsh (patch #2036802)