The RCCG Open Heaven Devotional is out at #500 but not available on google playstore yet. You can download it here

Users of Electronic copy of Open Heaven devotional written by The General Overseer of the Redeemed Christian Church of God popularly called Daddy G.O is now available for download. Those with debit card can download the application and use their debit card to
purchase the activation code and enjoy it. Those with the scratch card and those intending to buy online can follow this link http://iopenheavens.com/ and select the option suitable for their device and download it