While Android 5.1.1 is an older version, many essential apps still support it. Updating your Play Store APK ensures:
Your old Lollipop device can still be useful – you just need the right software. google play store apk download for android 51 1 better
Even with a "better" APK, Android 5.1.1 can sometimes be finicky. If the Store crashes after the update: Google Play Store APK Download for Android 5