About a week ago we launched our new documentation portal which has a better structure, modern look and feel and very nice API Reference section. But, we didn't do it the right way and we are sorry about it. What we did wrong -- we didn't publish the old documentation site URL but simply redirected to the new site. We are sorry about this. This has caused problems for people who were looking for old tutorials or other content.
The old site is still here and can be viewed via http://devcenter2.appery.io. We will keep it running for at least month and probably longer. Just keep in that mind that this site will no longer be updated and the most up to date content is now at http://docs.appery.io.
If there are tutorials you would like us to migrate to the new site, please let us know.