As of October 31, 2018, Microsoft Office 365 will no longer support TLS 1.0 and 1.1

[fefrei (Felix Freiberger)]

Just as a reference of what others are doing, GitHub (which admittedly has an audience that is rather likely to keep browsers up to date) is disabling TLS 1.0 and 1.1 now:

https://github.com/blog/2498-weak-cryptographic-standards-removal-notice