After you change your Apple ID, you need to use your new sign-in information with all Apple services that you use.
WHY ARE YOU TELLING US SO EARLY?
We know this might affect a large number of our users so in order to lessen the impact, we wanted to give users 6 months notice to change their email before making the switch.
We will continue to send periodic email reminders up until the March 9, 2020 deadline.
Once the March 9, 2020 deadline hits, users who still have not made the change to a new email address will be forced to change at that time.
WHAT HAPPENS TO ALL MY APPS, MUSIC, GAMES, ETC. THAT I'VE PURCHASED WITH MY APPLE ID?