How to install Apps that no longer support for iOs 6.1.6?

I mean some apps that I have in my cloud can't be installed to my iPhone 4,
because it require iOS 7.

Any tips?

Iphone 4 can run iOS 7 fine, you might have to download it as it's the last one for the 4 and apps won't be written for it much longer either. I have it on my iPhone 4 and it's fine, no problems.