With the recent CU2 update for Exchange Server 2019, Microsoft offers a new “hybrid modern authentication” to replace more suseptible older protocols which may be less secure

https://redmondmag.com/articles/2019/06/21/microsoft-disabling-exchange-protocols.aspx

The Exchange team, in a Friday announcement, explained how Exchange Server 2019 with Cumulative Update 2 (CU2) can help organizations rid themselves of old authentication protocols, which constitute a potential security risk.    CU2, released this week, notably brings the ability to disable old authentication protocols organizationwide, which is a new capability. The idea is to switch to using so-called “hybrid modern authentication” instead, which is deemed as being more secure.