InstaVR packager supported Android 64-bit and API 28 that are required by Google Play.
You can apply this change bu click "Make Package" button in Package tab and submit you newly packaged .apk file to Google Play.
For further detail 64-bit change, please read through the following article.
Get your apps ready for the 64-bit requirement: https://android-developers.googleblog.com/2019/01/get-your-apps-ready-for-64-bit.html