If you are still using a device running Android 5.1.1 Lollipop, you might find that the Google Play Store doesn't always update itself as smoothly as it used to. Manually downloading the latest compatible APK can fix "Server Error" messages, improve app compatibility, and give you a more stable experience. Why Update the Play Store on Android 5.1.1?
Once you have successfully installed the better APK, consider these optimizations to keep your Lollipop device running smoothly for another two years. google play store apk download for android 51 1 better