ios 7 transition

the main themes of ios 7:

• Deference. The UI helps users understand and interact with the content, but never competes with it.
• Clarity. Text is legible at every size, icons are precise andd lucid, adornments are subtle and appropriate, and a sharpened focus on functionality motivates the design.
• Depth. Visual layers and realistic motion heighten users's delight and understanding.

Things every app must do

• Update the app icon. In ios 7, app icons are 120 x 120 pixels (hign resolution).
• Update the lauch image to include the status bar area if it doesn't already do so.
• Support retina display and iPhone 5 in all your artwork and designs, if you're not already doing so.

Things every app should do

• Make sure that app content is discernible through translucent UI elements-- such as bars and keyboards-- and the transparent status bar. In ios 7, view controllers use full-screen layout.
• Redesign custom bar button icons. In ios 7, bar button icons are lighter in weight and have a different style.
• prepare for borderless buttons by moving away from supplying button background images and by reassessing your layout.
• examine your app for hard-coded UI values -- such as sizes and positions -- and replace them with those you derive dynamically from system-provided values. Use auto layout to help your app respond when layout changes are required.
• examine your app for places where the metrics and style changes of UIKit controls and views affect the layout and apparance. For example, switches are wider, grouped tables are no longer inset, and progress views are thinner. 
• adopt dynamic type. In ios 7, users can adjust the text size they see in apps. When you adopt dynamic type, you get text that responds appropriately to user-specified size changes.
• make sure your app doesn't respond inappropriately to the new control center gesture or to a navigation contoller's swipe to go back gesture, especially if you perform custom touch handling.
• revisit the use of drop shadows, gradients, and bezels. Because the ios 7 aesthetic is smooth and layered-- with much less emphasis on using visual effects to make UI elements look physical -- you may want to rethink these effects.
• if necessary, update your app to best practices for ios 6 -- such as auto layout and storyboards -- and ensure that the app uses no deprecated API.