Where does RIMM's growth come from?

I'm reading RIMM earning call tran:
1. "In Q3 of this year, almost half of net subscriber account additions were non-enterprise, versus just over 30% coming from non-enterprise in the third quarter of last year."

2. "the continuing strong replacement cycle. Over 40% of our subscriber base remains on devices launched two years or more ago, which we expect will continue to fuel the strong upgrade cycle going forward."