iCloud Drive versus iCloud what is the difference? Possible Bug.

I don't believe I have upgraded to iCloud drive on my windows PC, iPad V1, iPhone 4 or iPhone 5s - Is there a quick way to find out?

I am able to export iMovie content to Imove Theatre from my iPhone 4 to view on my apple TV but I cant do this from my IPhone 5s?

I just get a cloud up arrow on my iPhone 5s.

If I click on the square with an up arrow in IMovie Theatre on my iPhone 5s I just receive a message saying there is no connection to icloud or internet even though I am signed into icloud??

Is this a bug I have found?