Galaxy Ace 4 TWRP recovery will allow users to download and flash custom firmware and all sorts of hacks. Installing it will void the warranty of your phone. Download link is present at the bottom of this article. You will need an micro SD cad to flash it as the process requires you to copy the download twrp file to sd card.
* copy/move file to exSdCard/
* Reboot phone in RECOVERY MODE(press and hold Home + Power + Volume UP buttons)
* install twrp from extSdCard
* Wait until the flashing process is complete
You can find specs of the Samsung Galaxy Ace 4 here. TWRP is an optimized version of the clockwork mod recovery that does not accepts touch screen input and in that, one has to make use of the buttons in order to navigate. But with TWRP, you will be able to interact with the Galaxy ace 4 with touchscreen.