Hi,
About "app not installed" the problem is they didnt "sign" the apk, so some smartphones refuse to install it.
You can use this application to update the apk : https://play.google.com/store/apps/details?id=com.haibison.apksigner
I wrote this topic for dev team : https://forum.hentaiheroes.com/index.php?/topic/11703-android-app-cant-be-installed/
About "old version", It s ok for me, I downloaded and signed this file : https://content.hentaiclicker.com/game/mobile/release-hentaiclicker-v0.18.apk