We are moving to the cloud. Actually, the primary servers for MathSciNet already moved to cloud servers on October 17th of this year. We waited to make sure that there were no hiccups with the transition before making it public. There are now servers in Europe, North America, and Asia that are simultaneously updated. The cloud servers are now providing consistent and faster service.
The move to the cloud means a new address for MathSciNet: https://mathscinet.ams.org/mathscinet. The old address redirects you to this URL, so there is no immediate need to change links or bookmarks — but updating links is not a bad idea. This change did affect some proxy settings for off-site users, however. We have contacted librarians and have provided instructions on how to reset the proxy settings. If you are having a problem, write to email@example.com.
The move to the cloud also means that we will be retiring the five mirror servers at Rice University (Houston), IMPA (Rio de Janeiro), IRMA (Strasbourg), MPI (Bonn), and the University of Bielefeld (Bielefeld). For twenty years, these institutions provided better global access to the Mathematical Reviews database by hosting servers around the world. Over time, though, the technology of the web has evolved to a point where distributed access is now best provided by hosting sites on cloud servers. We are truly grateful to the five hosts. Over the next six months, as the mirror sites retire, their URLs will begin redirecting to the cloud servers.
This is the latest of the enhancements rolling out for MathSciNet. Sometimes they are quite visible, like the faceted searches released in January. Sometimes they are infrastructure, like this move to cloud servers. The internal changes are often best appreciated by not being noticed at all, except that your searches are a little faster and MathSciNet is always available.