I just disassembled the files and I found the main difference is that October release requires IE10 (mandatory), while November release made that requirement optional. Code: 300xxxx is released in October 2013, installation requires IE10. 317xxxx is released in November 2013, recommends but not require IE10. In file: \vs_XXX.exe > LocalizableStrings.xml [300xxxx] Line44: This version of Visual Studio requires Internet Explorer 10 which is currently not installed on your computer. Please install Internet Explorer 10 and then retry installing Visual Studio. [317xxxx] Line44: This version of Visual Studio works best with Internet Explorer 10 which is currently not installed on your computer. If you choose to continue, some features might not work as expected. In file: \vs_XXX.exe > BootstrapperApplicationData.xml [300xxxx] Line08: <UxBlocker ShortName="IE10Block" Type="Stop" ... Line16: <UxBundleInformation Id="BuildNumber" Value="12.0.21005.01" /> [317xxxx] Line08: <UxBlocker ShortName="IE10Block" Type="Warn" ... Line16: <UxBundleInformation Id="BuildNumber" Value="12.0.21005.13" /> The remaining differences are different GUID, nothing particular interesting.