Replace 140mm fork with 160mm on Remedy 7 27.5 possible? I'm Curious about whether it's possible or whether Remedy's frame is designed  for such a replacement. Some bicycles makes it possible to upgrade to longer forks. I searched in Google, some people say that it's bicycle dependent. So, who knows about it, can I do this with Remedy or it just doesn't matter?
FWIW, I have put 140mm-100mm adjustable forks on an XC bike designed for 100m forks. Going from 140mm to 160mm will change the geometry of the bike a bit, but a bike that already has a 140mm fork is pretty slack to begin with. 

Depending on the exact fork and how much you set up the sag, there may be little to no measurable difference between the two forks during "normal" riding. The slacker the head angle, the less difference a change in fork length makes. If you're planning on running it at "All mountain" sag values, then 

( 140 * .7 ) = 98 mm 

( 160 * .7 ) = 112 mm 

So the fork will only be about 1.4 cm longer during normal riding, and at a 68 degree head angle, you will barely notice the difference in height. This assumes
the two forks have roughly equal axle to crown measurements. 

If you want an official answer email trek and ask if putting the new fork on will void the frame warranty. 

http://www.trekbikes.com/us/en/support/contact/

If it were my bike, I'd do it without a second thought. But I love building franken bikes.