Facebook has now set a deadline of August 23 for the new tab width limit of 520 pixels to kick in. This follows our report earlier this week that the change, first announced 10 months ago, would take effect “in the coming weeks”. The current limit is 760 pixels and many page administrators have not revised tab sizes, despite the change being mooted since October last year.

To help page administrators with the transition, Facebook is to provide the ability to preview custom tabs in the new 520-pixel width next week so any necessary changes to layouts can take place before the limits become mandatory. All profile and page tabs will be resized automatically beginning the week of August 23.

Facebook also indicated that the previously announced removal of application boxes and descriptions will happen the same week. The social networking site plans to notify users via messaging in profile boxes and in the Help Center that the “boxes” tab, boxes on profiles and pages, and application info sections will be going away.

The Facebook Developer blog said: “These updates are designed to simplify navigation for users, reduce complexity for developers, and enable us to build the next generation of tools for growing your business with Facebook. We’ll share more of our plans for the roadmap in the coming weeks.”

The Developer Roadmap is in the process of being updated.