On March, 10th we will introduce a change in the availability of viewer data in apps. If the current viewer has installed the app, he is resolvable as viewer in every view and at every installation. It does not matter, if he is the current owner of the gadget or not.
Note that viewer-owner-separation checks like
if (data.get("viewer").hadError() || data.get("viewer").getData().getId() == null)
may not return the desired results anymore if you want to check if the viewer is the current owner, since the viewer will always be delivered correctly if he has installed the app. You can use the isOwner or isViewer methods instead as described at http://developer.studivz.net/wiki/index.php/Opensocial.Person_%28v0.8%29#opensocial.Person.isViewer. We will update our tutorial at http://developer.studivz.net/wiki/index.php/Lesson_11:_Separate_viewer_and_owner accordingly.
The second change is the resizing of the canvas view. The new dimensions will be 800 x 600 pixels. Of course like before the height of the app is flexible with the gadgets.window.adjustHeight method an can be enlarged up to 2000 pixels.
Most existing gadgets should be compatible with these changes but our support team will check each currently online app for compatibility regardless. If your app needs any changes, you will be notified via mail.
Also these changes will be available in our sandbox and documented in our wiki this week. Follow our Twitter account http://twitter.com/VZ_API_NEWS to receive an immediate notice of this, so that you can start testing and adjusting your apps if necessary.