Business Central is evolving faster than the old NAV. Every 6 months, Microsoft releases a new major version that may or may not break the changes. To keep up with the list of tables and functionalities that are deprecated, Microsoft provides some information about these breaking changes. The following links can provide you with what, why, and how to navigate around these deprecated features.
Deprecated Features
Deprecated Fields
https://docs.microsoft.com/en-us/dynamics365/business-central/dev-itpro/upgrade/deprecated-fields
Breaking Changes
https://github.com/microsoft/ALAppExtensions/blob/master/BREAKINGCHANGES.md