Hi Megan,

When the GMAT changes, it does so slowly. The last major change to the test was the introduction of the Bolded Statement question type several years ago, and that type doesn't even show up on every test-takers test. There have also been reports that recent RC passages are longer and more convoluted than they have been in the past, but there isn't (to my knowledge) any concrete confirmation that this is so. In other words, though older questions may differ slightly in the proportion of problem types and distribution of difficulty, they will still test the same concepts and the same strategies as modern questions. Newer stuff is better, but the older stuff will definitely help to prepare you for the GMAT.