how can i obtain ios 9.3.5 and itunes 12.3

I have an iphone 4s running ios 6.1.3. i'd like to get and upgrade on ios, but all that's available going thru settings is 7.1.2. The version of itunes i'm running doesn't have a small iphone icon on it, so i need to update to version 12.3.

all of the above is to transfer contacts and calendars to and iphone 5s i inherited from my grandson.