A) You'll find your current Magento version on backend footer (at center).
B) It depends on which version do you have. Can you tell us from which verstion to which new version do you want to upgrade?
I guess that you want to upgrade to Magento 220.127.116.11.
Remember to perform a full backup before start.
Also try to use a dev or local environment. Don't try this on a LIVE store until you're sure that all the process has worked.