C2DM Registration ID vs GCM Registration ID?

Question

I notice that Google has deprecated C2DM and changes it to GCM. Then, in its Migration docs, it states:

After receiving a response from GCM, the registration ID obtained must be sent to the application server. When doing this, the application should indicate that it is sending a GCM registration ID so that the server can distinguish it from existing C2DM registrations.

For anyone have migrated C2DM to GCM, is the registration ID in different format for both services? Because it states

the application should indicate that it is sending a GCM registration ID so that the server can distinguish it from existing C2DM registrations.

Thanks

Answer 1

The format is the same I believe but the registration ID is different for the two services. There needs to be indication in the application server because there is a different request to Google for GCM and C2DM.