The final version of Maemo SDK 4 is out. Like most other people I couldn't wait for the final release and I installed the beta version. The big question, when I did read about the final version was "how can I upgrade to the final version without installing it from scratch?!". Luckly one kind person helped me on maemo-developer mailing list, and suggested me to do a dist-upgrade from inside the Scratchbox environment. So, login into tour Scratchbox environment and execute this:
[sbox-SDK_BETA_X86: ~] > fakeroot apt-get update
[sbox-SDK_BETA_X86: ~] > fakeroot apt-get dist-upgrade
That's all! I don't know if this is the official method to do the upgrade, but it worked for me. I checked, after the upgrade, if I had the right packages installed, using this page: http://tablets-dev.nokia.com/4.0/4.0b_vs_4.0_content_comparison.html
and they were right.