Within our product we move more and more stuff in the .NET Core land. Last week we had a disussion around needed software requirements and in the .NET Framework land this question was always easy to answer:

.NET Framework 4.5 or higher.

With .NET Core the answer is sligthly different:

In theory major versions are compatible, e.g. if you compiled your app with .NET Core 3.0 and a .NET Core runtime 3.1 is the only installed 3.X runtime on the machine, this runtime is used.

This system is called “Framework-dependent apps roll forward” and sounds good.

The bad part

Unfortunately this didn’t work for us. Not sure why, but our app refuses to work because a .dll is not found or missing. The reason is currently not clear. Be aware that Microsoft has written a hint that such things might occure:

It’s possible that 3.0.5 and 3.1.0 behave differently, particularly for scenarios like serializing binary data.

The good part

With .NET Core we could ship the framework with our app and it should run fine wherever we deploy it.

Summery

Read the docs about the “app roll forward” approach if you have similar concerns, but test your app with that combination.

As a sidenote: 3.0 is not supported anymore, so it would be good to upgrade it to 3.1 anyway, but we might see a similar pattern with the next .NET Core versions.

Hope this helps!