There are a few ways to know when you get the play store update.
First, you can check the Google Play Store app page on the Google Play website. The date that you see under "Last Updated" is the date of the most recent version of the Play Store that is available for download.
Second, you can check your Android device's settings. To do this, go to the "Settings" menu, tap "About phone," and look for the "System updates" entry. If an update is available, you should see a message that says "Downloading," "Installing," or "Installing system update."
Finally, you can check for updates by going to the Play Store app itself. To do this, open the Play Store app, tap the menu button (three horizontal lines), and tap "Settings." In the "Settings" menu, tap "Auto-update apps." If the "Auto-update apps" setting is turned on, the Play Store will update apps automatically when updates are available.