May be a dumb question, but: I have an active SA until September 2015. Am I entitled to install "Subscription Update 1" since there may arise problems with my installation?

May be a dumb question, but: I have an active SA until September 2015. Am I entitled to install "Subscription Update 1" since there may arise problems with my installation?
Also when the time comes to renew my SA will it be converted to "Subscription"?