Iphone 4s :That common action or notification icon has been lost.. IDK what it is said?

I have an iphone 4s. I had that action/notification icon (say dock) has been lost. I cant restore it. I used it last time before i reset my device and

I have an iphone 4s. I had that action/notification icon (say dock) has been lost. I cant restore it. I used it last time before i reset my device and upgraded my ios. Is it due to new ios, dock has diappeared or is it some fault i have done.
Can i bring it back?
PS so sorry i dont know that icon name
iOS 9.3.1

or:I have an iphone 4s. I had that action/notification icon (say dock) has been lost. I cant restore it. I used it last time before i reset my device and upgraded my ios. Is it due to new ios, dock has diappeared or is it some fault i have done.Can i bring it back?PS so sorry i dont know that icon nameiOS 9.3.1

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