Update ' MultiDeviceAnnouncementsPush'

-MultiDeviceAnnouncementsPush.md

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+So if we modify the library and clients as described in MultiDeviceAnnouncementsPOC
+how do we keep it up to date when a friend changes his devices.
+
+If we know the PersonaID, how is the library code table of PersonaID to ToxID mapping updated. We want this to be mainly automatic without bothering the user.
+
+We would need to modify the profile code to save a copy if the mapping table,
+so that when we start up a client, the mapping table is filled with last good values from the profile.
+
+Lets say we have a friend, and we know his ToxID. We derive his PersonaID by setting the checksum to 0s. We want to watch the DHT announcements for a blob of information that will update our PersonaID mapping to his active ToxID. 
+
+Note that if we do so that destroys the possibility to simply derive the PersonaID from the ToxID. That derivation is a startup mechanism to get the network switched over to client-facing PersonaIDs, and after that we rely on the profile to boostrap the table.
+
+The library and the clients add one new feature: the ability of the client to express interest in a PersonaID and to update the table with the new ToxID found un the blob when it arrives.
+
+Some clients may let the user decide whether of not to accept a blob update when it arrives.
+