Some Yammer IDs returned by the REST API have grown beyond 32 bits
It has come to our attention that some customer and partner apps that have been developed against our API have expected the IDs to be 32 bit.
The Yammer REST API exposes a number of IDs of various objects inside Yammer including MessageID, UserID, GroupID, etc.
These IDs are not 32 bit in Yammer, and some now have moved beyond the amount of memory storable by 32 bits. As exposed by our Yammer API Yammer IDs are JSON integers which at the time of this posting allow up to 53 bits.
Restricting your variables that contain Yammer IDs to be 32 bit integers will cause your apps to be unreliable at best, and most likely they will crash.