Installing an Apple TV 4 app on Apple TV 2 I have seen easy methods to jailbreak apple tv 2. I would like to know if anyone has tried to manually install an apple tv 4 app on a jailbroken apple tv 2. Is that possible at all? 

Specific example: Bell Canada has introduced its Fibe Alt TV app to be used only on apple tv v4, I was wondering if that could be manually installed on an apple tv 2, or, I have to buy an Apple tv 4 anyways!
No, is the short answer.

Apple TV gen 2 and Apple TV 4 run completely different operating systems. There is no compatibility in software between them.