Cant Submit Android game

Hi there.

Few days I am trying to upload Android game as well to present for this SummerEu4 Jam. But Fisrt things first I cannot upload anything which is not apk. and second I just got this message from Google Play:

Hello Google Play Developer,

We rejected Real 3D Escape: The Sixth Element, with package name com.Creatiwell.Real3DEscape1, for violating our Malicious Behavior or User Data policy. If you submitted an update, the previous version of your app is still available on Google Play.

This app uses software that contains security vulnerabilities for users or allows the collection of user data without proper disclosure.

Below is the list of issues and the corresponding APK versions that were detected in your recent submission. Please upgrade your app(s) as soon as possible and increment the version number of the upgraded APK.
Libpng library

The vulnerabilities were fixed in libpng v1.0.66, v.1.2.56, v.1.4.19, v1.5.26 or higher. You can find more information about how resolve the issue in this Google Help Center article.

Help please?