Bb os 7.1 to bb10

Not sure if this was answered previously but will the complete transfer of data from our current legacy BB OS to BB10 go through without a problem ?

I saw on another website that we will need to download some apps that might not be native for ex: Password Keeper on our BB10

Its an app that i use constantly so if i dont download it on my Z10 b4 doing the transfer will the transfer of data fail?