Please remove all previous version of Greenify and Donation Package at first!!!
Install Xposed installer APK
Install Greenify_2.3 (build 4).apk
Open Xposed installer, select greenify inside modules tab, open framework tab then press install/update & reboot

This version supports greenifing system apps, works fine on Android Runtime (ART) In KitKat!

Updated: November 3, 2014
Current Version: 2.5 Beta 4 patched

tusfiles: http://dl.apkpro.net/7KL
zippy :   http://dl.apkpro.net/7KM
devhost:  http://dl.apkpro.net/7KN

==========OLD VERSION==========
Version: 2.3 Build 4 + Donation Package 2.3
tusfiles: http://dl.apkpro.net/5R3
hugefiles: http://dl.apkpro.net/5R4
zippy : http://dl.apkpro.net/5R5

==========OLD VERSION==========
Version: 2.2 Build 6 + Donation Package 2.3
tusfiles: http://dl.apkpro.net/4ss
hugefiles: http://dl.apkpro.net/4st
zippy : http://dl.apkpro.net/4su
devhost: http://dl.apkpro.net/4sv
sharebeast: http://dl.apkpro.net/4sw

==========OLD VERSION==========
Version: 2.2 Build 3 + Donation Package 2.3
tusfiles: http://dl.apkpro.net/4gC
hugefiles: http://dl.apkpro.net/4gD
zippy : http://dl.apkpro.net/4gE
sharebeast: http://dl.apkpro.net/4gF