Subscriber merge to your official channel
If you're an artist on YouTube and you have an Official Artist Channel, we will be merging subscribers from your related Topic Channel and Partner-provided channel (as relevant) onto your channel. You may see an increase in your Official Artist Channel subscriber count as subscribers are merged. Now, all of your subscribers will be updated with new music videos uploaded to the Official Artist Channel and your other channels. This should help you promote new music more effectively and provide scale when you want to engage with fans.
Now fans will have a single place to subscribe, i.e. your Official Artist Channel. The subscribe button and subscriber count will no longer be displayed on your Topic channel or Partner-provided channel.