The Nikon D3300 camera is rumored to be replaced in 2016. I do not have an exact date, but there is a very good chance that the next camera announcement could be the D3500 (or D3400?). The new camera will be compatible with SnapBridge and is expected to have a 24MP sensor - this is all I have for now.
Solving AF problems: 8 common autofocus problems and their solutions by Steve Perry (website | YouTube | Facebook, you can check also his previous [NR] posts here):
It happens to every photographer at one time or another, and it can cause more frustration than baptizing a cat. You’re happily shooting away at your favorite subject, the action subsides, and you quickly check the images on the back of your camera - but something’s wrong. Instead of the crisp, biting sharpness you were expecting, you see photos soft enough to make pillows.