Azure App Service and .Net Framework versions

Question

I have an Asp.Net Web API set to target .NET 4.6.1 which is published to an Azure App Service.

I received a notification from Microsoft about the imminent move to .NET 4.8 for Azure App Service.

The notification recommends I test my applications locally.

I can see that v4.6.1 is an installed version of .NET framework for my Azure App Service:

Two questions:

1. Given v4.6.1 exists will my Web API continue to use v4.6.1 regardless of the later versions of .NET framework that are present?
2. What (if any) testing is needed prior to the v4.8 App Service Update? Is it just a case of building it locally using v4.8 to confirm it builds/runs, or is a thorough batch of regression testing warranted?

Answer 1

1. "Given v4.6.1 exists" is not a valid assumption. What you saw is merely the referenced assemblies installed on your local machine for development. Even if your code is compiled against v4.6.1 referenced assemblies, at runtime it is executed by the actual runtime version (v4.6.1 or above), so the actual behaviors are controlled by that runtime.

2. That's another subjective thing. Most enterprises will choose a thorough batch of regression testing, though individual developers might choose to simply compile/run.