Inno Setup 6 introduced a number of significant enhancements including:

OS requirements change: Windows 2000, XP, and Server 2003 are no longer supported. Windows Vista is the minimum supported operating system.

Change in default behavior: Starting with Inno Setup 6.1 the [Setup] section directive MinVersion defaults to 6.1sp1, so by default Setup will not run on Windows Vista or on versions of Windows 7 and Windows Server 2008 R2 which have not been updated. Setting MinVersion to 6.0 to allow Setup to run on Windows Vista is supported but not recommended: Windows Vista doesn’t support some of Setup’s security measures against potential DLL preloading attacks so these have to be removed by the compiler if MinVersion is below 6.1 making your installer less secure on all versions of Windows.

Change in default behavior: Starting with Inno Setup 6 there’s only one version available: Unicode Inno Setup. Unicode Inno Setup has been available for since 2009 but in case you have not yet updated to it: please see the Unicode Inno Setup topic in the help file for more information. Basically, unless you’re using [Code] to make DLL calls with string parameters you shouldn’t have to make any changes to your script.

What’s new in this version?

Read more: https://jrsoftware.org/isdl.php/hu-hu/