Minecraft Update 1.9- "Replace" or "Keep Both"?

I have downloaded the new update for Minecraft 1.9 and when I drag the "Minecraft" block to applications, it asks to "Replace" or "Keep Both". I want

I have downloaded the new update for Minecraft 1.9 and when I drag the "Minecraft" block to applications, it asks to "Replace" or "Keep Both". I want to keep my worlds and server information, as I have lots of items on two. I'm using a mac, and need answers. Thank you!

or:I have downloaded the new update for Minecraft 1.9 and when I drag the \"Minecraft\" block to applications, it asks to \"Replace\" or \"Keep Both\". I want to keep my worlds and server information, as I have lots of items on two. I'm using a mac, and need answers. Thank you!

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