You can use the version you have for as long as you like. But if you've lost it, then you can get another copy "if" your pro was purchased less than 6 months ago. I always make backups of each version. Around the end of the 6 month period, you can repurchase pro at a discount. If you still have the active email account then check here.

Oh where'd deepblue come from? Long time no hear!