is atv3 jailbreakable_

Nope

The Highlander said:

Just wondering.... Couldn´t find a definite answer on it... i know atv2 is (i have one) but I was wondering if it was worthwhile to upgrade to get 1080p.

Click to expand...

No jailbreak yet - and many people think there never will be.

No.

Also, check here:
https://forums.macrumors.com/threads/1512025/

No jailbreak but you can still use plex , You can use Plexnet to make trailers app behave as Plex app, been using it some time , made ATV3 more useful.

Check here https://github.com/iBaa/PlexConnect/wiki