If you are holding on to a really old Android device - one that's running Android 2.3.7 (Gingerbread) or earlier - then take note that you won't be able to use your Google account to sign into apps like Gmail or YouTube on it from the end of September. As per a forum post from Google, the functionality for affected devices is stopping on September 27, though if you really need to you can still access these services on ancient hardware through the built-in web browser.

Link: The oldest Android devices won't be able to use Google sign-ins from September
via http://www.techradar.com