Use APKPure App
Get Disguise for Facebook old version APK for Android
The Best Client for FB Fast! Reliable! Battery Saving!
Enjoy a Beautiful material design client with not having to worry about it draining you battery in the background, or slowing down your phone.
Features
*Notifications
*Faster Android Phone
*Improved Battery life
*Material
*Custom Messenger
Here is a article with more information:
http://phandroid.com/2016/01/26/facebook-makes-phone-slow/