
Are the following mentions coreferent?:
<m> upgrade </m> in As rumored, new 11 - inch and 13 - inch MacBook Air models have just been officially announced by Apple at WWDC 2012. Unsurprisingly, Apple is keeping pace with competitors with the addition of Ivy Bridge to its slimmest line of laptops. 
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<m> upgrade </m> in The only hardware release at Macworld Expo 2009 was a predictable unibody upgrade for the 17-inch MacBook Pro, which Apple reports will have an eight-hour battery life. 