Even though this version of Mac OS X is 10.9, I don't think Apple is going to make a major, from scratch renewal of Mac OS and name it XI. (11) So I believe it's going to be called 10.10. Now that they left cat names behind and moved on to locations in California. We can start guessing and making a database of guesses for the next one. I say; OS X Yosemite, 10.10.