This is a phone software update, certainly nothing to be concerned about, as well as improvements may also contain security updates and will need to be downloaded and installed to the phone by clicking the link preferably over a WiFi connection.
You don't mention the phone you are using, there is further information from device guides here
To benefit form a new SIM, live chat will help or a Vodafone store will complete a SIM swap. Vodafone are very security conscious about blank SIMs make sure you have good ID with you if going into a store for a SIM swap.
