On March 1, 2018, Microsoft Office 365 will disable support for TLS 1.0 and 1.1. This means that, starting on March 1, 2018, all client-server and browser-server combinations must use TLS 1.2 or later protocol versions to be able to connect without issues to Office 365 services. This may require certain client-server and browser-server combinations to be updated.
This is going to directly affect anyone who has TLS 1.0 on in IE to interface with financial institutions that still use it (i.e. Trusteer) or web-based applications that also use it (i.e. Yardi). They’re going to have to use Firefox/Chrome to get to their email instead, is really all it is.