We have recently enabled gifting notifications in the updated client, which will notify players about the gifts they receive from now on. However, as this is the first time we enabled this feature in the updated client, you may get notifications for the gifts you received in the past, the first time you log in.
For example, if you previously unlocked a new icon during the Snowdown event and haven't logged in to the legacy client since then, this new update will display a notification for that unlock/gift the next time you log in to the updated client.
We're aware that it may be confusing to receive notifications for gifts received in the past as if they were new, so we wanted to give you a heads up and provide more context on the update. :)