Add a common props file for TFM
ADD
Common.props
+<Project>
+ <PropertyGroup>
+ <TargetFrameworks>net5.0;netcoreapp3.1</TargetFrameworks>
+ </PropertyGroup>
+</Project>
\ No newline at end of file

MODIFY
Directory.Build.props
Directory.Build.props
<Project>
<PropertyGroup>
- <TargetFrameworks>net5.0;netcoreapp3.1</TargetFrameworks>
<LangVersion>9.0</LangVersion>
<Nullable>enable</Nullable>
<ProductName Condition="'$(ProductName)'==''">Chapter$(ChapterNumber)</ProductName>

MODIFY
EssentialCSharp.sln
EssentialCSharp.sln
@@ -10,6 +10,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
after.EssentialCSharp.sln.targets = after.EssentialCSharp.sln.targets
src\Chapter.props = src\Chapter.props
src\ChapterTests.props = src\ChapterTests.props
+ Common.props = Common.props
Directory.Build.props = Directory.Build.props
Directory.Build.targets = Directory.Build.targets
README.md = README.md

MODIFY
src/Chapter.props
src/Chapter.props
<Project>
+ <Import Project="../Common.props"/>
<PropertyGroup>
<OutputType>Exe</OutputType>
<StartupObject>AddisonWesley.Michaelis.EssentialCSharp.Shared.Program</StartupObject>

MODIFY
src/ChapterTests.props
src/ChapterTests.props
<Project>
+ <Import Project="../Common.props"/>
<PropertyGroup>
<ProductName>$(ProductName).Tests</ProductName>
</PropertyGroup>

Add a common props file for TFM (#323)