Greenify (Donation Package) is the paid version of the Greenify app, it costs $2.99 and has zero in app purchases.
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Pro Hibernate overly active apps to save battery
Greenify's mane function is to hibernate any installed apps. This allows users to to quell overly active apps that are draining their battery without having to delete them. This can be done with or without ROOT.
Pro Has extra experimental features over the free version
The Greenify (Donation Package) has a few extra experimental features that the free version does not offer. They require ROOT and the Xposed module to be installed. Using these features can help with the compatibility of the rest of the Greenify app, which is a big plus.
Pro Even works without ROOT
Greenify even offers battery savings to non ROOT devices, though it may be limited compared to what can be done with ROOT and Xposed.
Con Greenifying without ROOT has to be done manually each time
When using Greenify without ROOT access to hibernate apps, it has to be done manually each time. There is a widget and shortcut that users can set to their home screen to make this action a bit easier though.