Last compatible version app on iPhone 4s?

I've heard that iPhone added a new feature after they released iOS 7,
Unfortunately I'm still on iOS 5.1.2,
But I can't download such latest compatible version of apps, such as instagram, facebook, etc.
Is there any way to download the latest version? Please tell.

Is it possible to jailbreak iPhone 5S on ios7 yet?

I currently have an iPhone 4S, which is jailbroken. I plan to upgrade to the iphone 5S but only want to do it when it is jailbreakable, so is there an iPhone 5S ios 7 jailbreak available at the moment?

How to improve my mental health?

I'm looking for anything within reach that can help me better my mental or brains health. I'm 19 and I saw somewhere that the brains mental peak drops around the age of 21, I doubt it a little though. I'm looking for advice, so should I read more or I even heard meditating helps but maybe you guys can enlighten me more on it. I also got to mention financially I'm not… Well I'm poor but I got this iPhone 5 and I've been trying to see if it can help me on venturing towards comprehending things so I can better improve my life and then enlighten the less fortunate as I too share once was oppressed by the absence of a formal education, environment, family or nourishment… Sorry downloaded that dictionary app. Pretty awesome synonyms feature though, so please anything would help and I appreciate it. I'm lucky I got this, It's hard to even have a home phone or some food in the fridge. Umm yeah and anything would help as I had a rough life mentally I wasn't healthy or normal too quiet or I think it's called an introvert but I try to improve myself everyday physically and mentally in any way so again I'd appreciate it.