In case you're wondering; I 'upgraded' my Squarespace 5 website to the new Squarespace 6 platform.
Most of the data had been migrated, but there might some some files/photos/posts left behind. For those items, you can still access the old website through beta.redelijkheid.com. Just replace the www for beta, and everything should work.
If you have questions, you can contact me through the contact page.