Should I upgrade to iCloud Photo Library?

[jakudo]

Hello,

I have a macbook witch Yosemite, iPad with iOS8 and iPhone 4 with iOS7.
What happen if I migrate the photos to iCloud Photo Library? Will it work on iPhone with iOS7?

 

[EDiTOR9]

Hello,

I have a macbook witch Yosemite, iPad with iOS8 and iPhone 4 with iOS7.
What happen if I migrate the photos to iCloud Photo Library? Will it work on iPhone with iOS7?

I'm have the same setup as you do. When I take pictures and want to share with my wife they all show up on my iPhone's shared streams. These same pics are just "iCloud Photo Sharing" on iOS 8.