Upgrade from Xcode 4.2 to 4.3

1. After installing Xcode 4.3 via the App Store you may feel like you're finished.

2. But the process is not yet complete and you'll be surprised if you keep using the Xcode icon in your dock to launch, as there will be no apparent changes to Xcode.
3. As pointed out in this blog, the key is to continue the installation process by opening the newer Xcode via Spotlight. Once the additional components installation is finished, you will have the option to uninstall old Xcode installations like 4.2, which you should most definitely make use of!
4. Afterwards if you make use of the agvtool, and you run into some problems because of cornercases that the installer does not address ... you could have used instructions from http://doronkatz.com/upgrading-to-xcode-43-and-solving-the-develop ... but they seem to have been taken down :(
5. If you are facing problems with MacPorts, then that may be because:
   • you need to update to MacPorts 2.0.4
   • or even if you've done that, the particular "port install foo" may need to be done via the workaround prescribed here: https://trac.macports.org/wiki/ProblemHotlist