BC 17, Table Sales price and resource price is marked for removal:

https://docs.microsoft.com/en-us/dynamics365/business-central/dev-itpro/developer/devenv-extending-best-price-calculations

That's how the new pricing will work. Sadly MS haven't activated the UI for the feature yet, so it's not accessible in the client right now (as of Wave2 2020). This is kind of concerning, since as developers we want to get rid of the warnings and do stuff the right way, on the other hand we don't really get the chance to in this case (unless you want to do temporary changes you have to roll back again when the feature comes).

There're some posts in the BC-Dev yammer group though stating that they are working on it and will ship it with the next upcoming minor update.

sometime next year, MS communicated that obsolete functionality will stay in the Application for at least a year after beeing marked obsolete before beeing removed if i remember correctly.