* Added new [Setup] section directive: SignedUninstaller, which makes it possible to attach a digital signature to the uninstaller program (unins???.exe). When the uninstaller has a valid digital signature, Windows Vista users will not see an "unidentified program" warning when launching it from outside of Control Panel.
* Added new [Setup] section directive: SignedUninstallerDir.
* Check functions associated with [Tasks] entries are now called when the Select Tasks wizard page is entered. Previously, they were called prior to the wizard being shown, which meant they couldn't depend on the user's selections in preceding wizard pages. (There are plans to make the same change to [Components] in the future.)
* Brought back the pre-5.1.13 duplicate [Components]/[Tasks] entry semantics. For example, in the following case:

[Tasks]
Name: foo; Description: "foo #1"; Components: bar
Name: foo; Description: "foo #2"; Components: not bar
Name: foo\child; Description: "foo\child"

"foo\child" will now, once again, be shown regardless of which "foo" is conditionally created.
* Pascal Scripting: "files:" function imports may now include multiple filenames. "files:A.dll,B.dll" will cause both A.dll and B.dll to be extracted before A.dll is loaded.
* On Windows Vista, Setup no longer alters the uninstaller program's manifest resource to request elevation, because this would invalidate a digital signature. Instead, the uninstaller now respawns itself when elevation is required, much like Setup does beginning with version 5.2.0.
* The uninstall program's version is now 51.49.0.0.
* Minor tweaks.