My alarm used to work with Nest until Simplisafe sent out an update in November and now it no longer works. After 40 minutes on hold with tech support, the rep was no help even after putting me on hold numerous times. She returns the last pickup and tells me "our engineers are aware and working on the problem."
Last time I heard that response from Simplisafe was two years when they claimed that "the engineers are aware and working on the problem of having multi-user access". The forum suggests that there has been no progress despite hundreds of requests for this function.