I think When you are primed to make an impression on each one of those application introduces, your server might then organize and make an impression on GCM defining which 'enrollment ids' ought to accept the message. That is carried out in 1000 id clusters, however yes you can send to a huge number of id's like this.
We've been getting this kind of inquiry a great deal recently, so we assemble an article with some decent graphs to help represent the methodology:
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