Recent updates have introduced a technical requirement that changes the minimum TLS version a client can use to now be v1.2. This version is already 12 years old, so any modern client will support it.
Old windows 7 and 8 clients do support it, but require a setting enabled as per https://docs.microsoft.com/en-us/archive/blogs/schrimsher/enabling-tls-1-1-and-1-2-in-outlook-on-windows-7
A quote regarding the change: “There has been talk of disabling TLS 1.0 for quite some time. The original deadline was June 30, 2016, but this has been extended until June 30, 2018.”