I deleted the DJI GO APP from my last phone because it drained the battery, fast, in hours.  With the latest update and a new phone I thought I'd try again, but the same occurs.  Will DJI be fixing this, or have they abandon the p3's?  Still getting constant emi warnings too.  

I have a P3P and the DJI Go app on an iPhone 6 and an iPad mini 2 and have not experienced significant battery draining when the app is not in use.  When the app is used,  the devices do use power and get warm, but not what I would consider excessive.  Even after a couple batteries of P3P flight, I still have plenty of phone/pad battery left.

If you have a P3 Standard, then there is no physical connection between the aircraft, RC unit and phone, so it cannot drain the phone battery. You phone battery is probably on its way out and needs replacing.

Strange, this have never happened too me, running Android

I don't believe it is the app. I am an android user myself, and have had several devices for a couple years now, and never had an issue with draining my battery like you mentioned. I also have several friends that use IOS devices, and I asked them the question and received the same answer....no problem like that. Can't imagine especially with you new device you have that same problem. Are you actually leaving the app open?, or are you saying by just having it installed is causing the problem?

Could you clarify what mobile device you're using and whether or not you're running any other programs in the background?

I bought a new LG Stylo 2 plus. Had the same problem with my last phone.  I installed the app on my new phone and noticed that the battery went down much faster.  I usually lose 1/4 to 1/2 battery during a 8+ hr shift, but with the app installed it was nearly drained. I deleted the app and things were back to normal.  I don't have this problem with my iPad mini 3.