Will I understand "War for the Planet of the Apes" if I don't watch the rest of the movies? [duplicate]

Planet of the Apes has been rebooted twice I believe. The older versions, you can easily pass as they have no direct relation to the movie, other than thematically (and with a few names).

Regarding the latest reboot, we can't know for sure how much the 3rd movie, War of the Planet of the Apes (2017) will require to watch the previous movies. But watching the 2nd movie, Dawn of the Planet of the Apes (2014), it's very understandable solo, with the exception of a single scene (a symbol from the first movie is used, and you might not understand why it works, but the results are still easy to understand).

I'd still recommend to watch at least the 1st movie, Rise of the Planet of the Apes (2011), as it explores deeply the main character, and gives a background for his actions and events in the 2nd movie. The 2nd movie, you probably can pass without missing much, although I'd personally watch it as well. The 3rd movie seems to be more in line with the 2nd movie, but I'm only judging by the trailer.

A good way of understanding Planet of the Apes:

https://en.wikipedia.org/wiki/Planet_of_the_Apes

Another source:

https://en.wikipedia.org/wiki/Planet_of_the_Apes_(2001_film)

And yet another:

https://en.wikipedia.org/wiki/Planet_of_the_Apes_(1968_film)

Yes, it is a good idea if you watch the movie to gain a better understanding of the plot throughout the entire story, yet again if you can't obtain the movies for some reason, you can do some research which I have provided some above.

Sometimes all it takes is a little bit of searching to get what you need. But I recommend you watch the movies as well as research because you can't always get the full story by researching or just watching movies so you need to do both.