The DUN upgrade provides additional features for the DUN components that were first introduced in Windows 95. The DUN 1.4 release includes all of the features of all previous DUN releases, as well as those that are included in the Integrated Services Digital Network (ISDN) version 1.1 release. DUN features include PPTP client support, 128-bit encryption, support for internal ISDN adapters, multilink support, and connection-time scripting to automate non-standard login connections. The DUN upgrade can be applied to any version of Windows 95. However, you cannot install the Windows 95 version of this upgrade on any other version of Windows.