In Previous we have discuss how to enable upcoming changes on your application.
Now we will discuss what will change on September 5th, 2012.
The following changes will go into effect on September 5th, 2012:
1- Deleting FB.Canvas.setAutoResize
- Originally scheduled for January 1, 2011 .Facebook will renamed FB.Canvas.setAutoResize to FB.Canvas.setAutoGrow so that the method more accurately represents its function.
FB.Canvas.setAutoResize will stop working on August 1st. Facebook will completely delete the function on September 5th (if you call it you will get an “undefined function” error).
2 – Open Graph Publishing
Custom actions for reading articles and watching videos must use built-in actions. Built-in watch and read actions can only be published after someone engages with the content for 10 or more seconds.
The following changes can all be enabled/disabled using the “September 2012 Breaking Changes” migration until September 5th when they will go into effect permanently for everyone:
3- Facebook is Renaming ‘likes’ property of Comments and ‘votes’ property of QuestionOptions.
facebook will be renaming the likes property of the Comment object to like_count and the votes property of the QuestionOption to vote_count.
4- Minor change to admin.getAppProperties call
When making an admin.getAppProperties call, we will now return an empty iOS Bundle ID as  instead of [""].
5- Returning actual size in photo_src table
We will start returning the actual size, height, and width of photos in the photo_src FQL table instead of the dimensions of the bounding box.
Sources is taken from Facebook developer zone and SDK change log.