We have Google Play Store v8.1.31 APK update here to download for all of you. We have the authentic source of APK file of this update, Go through the post to get the APK file.
We will update this post with the proper change-log of this update.
Below are the app details:
Version: 8.1.31.S-all  [PR] 165266818 (80813100)
16.14 MB (16,919,459 bytes)
Min: Android 4.0 (Ice Cream Sandwich, API 14)
Target: Android 7.1 (Nougat MR1, API 25)
240, 320, 480dpi
MD5, SHA-1, SHA-256 signatures
Supports Android Auto, Supports Cardboard
Uploaded August 18, 2017 at 3:01AM GMT+0530 by MNBooZe (OpenGApps.org)
Click on the below link to download the APK File of this update