diff --git a/build-common/NHibernate.props b/build-common/NHibernate.props
index d4fa4e5f508..2cf1d0e64d7 100644
--- a/build-common/NHibernate.props
+++ b/build-common/NHibernate.props
@@ -14,6 +14,9 @@
 
     <NhAppTargetFrameworks Condition ="$(NhAppTargetFrameworks) == ''">net461;netcoreapp2.0</NhAppTargetFrameworks>
     <NhLibTargetFrameworks Condition ="$(NhLibTargetFrameworks) == ''">net461;netcoreapp2.0;netstandard2.0</NhLibTargetFrameworks>
+    <NhNetFx>false</NhNetFx>
+    <NhNetFx Condition="$(TargetFramework.StartsWith('net4'))">true</NhNetFx>
+    <DefineConstants Condition="$(NhNetFx) AND $(NhVbNet) == ''" >NETFX;$(DefineConstants)</DefineConstants>
 
     <Product>NHibernate</Product>
     <Company>NHibernate.info</Company>
diff --git a/default.build b/default.build
index 8201995f47a..f7de77b6dfc 100644
--- a/default.build
+++ b/default.build
@@ -6,6 +6,7 @@
 >
 
 	<property name="root.dir" value="." />
+	<property name="target.dir" value="net461" />
 
 	<include buildfile="${root.dir}/build-common/common.xml" />
 
@@ -144,7 +145,7 @@
 	</target>
 
 	<target name="put-connection-settings-into-app-config">
-		<property name="app.config" value="src/${test.file}/bin/${build.config}/net461/${test.file}.dll.config" />
+		<property name="app.config" value="src/${test.file}/bin/${build.config}/${target.dir}/${test.file}.dll.config" />
 		<call target="put-connection-settings-into-defined-app-config" />
 	</target>
 
@@ -156,7 +157,7 @@
 
 	<target name="run-tests" depends="find-nunit" description="Run NUnit tests">
 		<exec program="${nunit-console}" failonerror="${not property::exists(test.file + '.IgnoreFail')}">
-			<arg value="${root.dir}/src/${test.file}/bin/${build.config}/net461/${test.file}.dll" />
+			<arg value="${root.dir}/src/${test.file}/bin/${build.config}/${target.dir}/${test.file}.dll" />
 			<arg value="--result=${testresults.dir}/${test.file}.dll-results.xml;format=nunit2" />
 			<arg value="--teamcity" if="${property::exists('config.teamcity')}" />
 			<arg value="--x86" unless="${property::exists('nunit-x64')}" />
@@ -164,7 +165,7 @@
 	</target>
 
 	<target name="remove-connection-settings-from-app-config">
-		<property name="app.config" value="${root.dir}/src/${test.file}/bin/${build.config}/net461/${test.file}.dll.config" />
+		<property name="app.config" value="${root.dir}/src/${test.file}/bin/${build.config}/${target.dir}/${test.file}.dll.config" />
 
 		<xmlpoke
 			file="${app.config}"
@@ -246,7 +247,7 @@
 			</fileset>
 		</copy>
 		<copy todir="${bin-pack.required}">
-			<fileset basedir="${root.dir}/src/NHibernate/bin/${build.config}/net461/">
+			<fileset basedir="${root.dir}/src/NHibernate/bin/${build.config}/${target.dir}/">
 				<include name="Antlr3.Runtime.???" />
 				<include name="Iesi.Collections.???" />
 				<include name="NHibernate.???" />
@@ -263,7 +264,7 @@
 			</fileset>
 		</copy>
 		<copy todir="${bin-pack.tests}">
-			<fileset basedir="${root.dir}/src/NHibernate.Test/bin/${build.config}/net461">
+			<fileset basedir="${root.dir}/src/NHibernate.Test/bin/${build.config}/${target.dir}">
 				<include name="log4net*" />
 				<include name="NHibernate.DomainModel.*" />
 				<include name="NHibernate.Test.*" />
@@ -271,12 +272,12 @@
 			</fileset>
 		</copy>
 		<copy todir="${bin-pack.tests}">
-			<fileset basedir="${root.dir}/src/NHibernate.Test.VisualBasic/bin/${build.config}/net461">
+			<fileset basedir="${root.dir}/src/NHibernate.Test.VisualBasic/bin/${build.config}/${target.dir}">
 				<include name="NHibernate.Test.VisualBasic.*" />
 			</fileset>
 		</copy>
 		<copy todir="${bin-pack.tests}">
-			<fileset basedir="${root.dir}/src/NHibernate.TestDatabaseSetup/bin/${build.config}/net461">
+			<fileset basedir="${root.dir}/src/NHibernate.TestDatabaseSetup/bin/${build.config}/${target.dir}">
 				<include name="NHibernate.TestDatabaseSetup.*" />
 			</fileset>
 		</copy>
diff --git a/src/NHibernate.DomainModel/NHibernate.DomainModel.csproj b/src/NHibernate.DomainModel/NHibernate.DomainModel.csproj
index 751f0f7380e..95134f11e0c 100644
--- a/src/NHibernate.DomainModel/NHibernate.DomainModel.csproj
+++ b/src/NHibernate.DomainModel/NHibernate.DomainModel.csproj
@@ -6,9 +6,6 @@
     <IsTestProject>true</IsTestProject>
     <NoWarn>$(NoWarn);3001;3002;3003;3005</NoWarn>
   </PropertyGroup>
-  <PropertyGroup Condition="'$(TargetFramework)' == 'net461'">
-    <DefineConstants>NETFX;$(DefineConstants)</DefineConstants>
-  </PropertyGroup>
   <ItemGroup>
     <None Remove="**\*.hbm.xml" />
   </ItemGroup>
diff --git a/src/NHibernate.Test.VisualBasic/NHibernate.Test.VisualBasic.vbproj b/src/NHibernate.Test.VisualBasic/NHibernate.Test.VisualBasic.vbproj
index 613f61cdd69..90eb6a22eb8 100644
--- a/src/NHibernate.Test.VisualBasic/NHibernate.Test.VisualBasic.vbproj
+++ b/src/NHibernate.Test.VisualBasic/NHibernate.Test.VisualBasic.vbproj
@@ -1,4 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <NhVbNet>true</NhVbNet>
+  </PropertyGroup>
   <Import Project="../../build-common/NHibernate.props" />
   <PropertyGroup>
     <Description>The Visual Basic Unit Tests for NHibernate.</Description>
@@ -13,8 +16,8 @@
     <OutputType>Exe</OutputType>
     <GenerateProgramFile>false</GenerateProgramFile>
   </PropertyGroup>
-  <PropertyGroup Condition="'$(TargetFramework)' == 'net461'">
-    <DefineConstants>NET461,$(DefineConstants)</DefineConstants>
+  <PropertyGroup Condition="$(NhNetFx)">
+    <DefineConstants>NETFX,$(DefineConstants)</DefineConstants>
   </PropertyGroup>
   <ItemGroup>
     <None Remove="**\*.hbm.xml" />
@@ -41,4 +44,4 @@
   <ItemGroup>
     <Service Include="{82a7f48d-3b50-4b1e-b82e-3ada8210c358}" />
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/src/NHibernate.Test/NHibernate.Test.csproj b/src/NHibernate.Test/NHibernate.Test.csproj
index e6137c3a4ba..9a2cf6767a2 100644
--- a/src/NHibernate.Test/NHibernate.Test.csproj
+++ b/src/NHibernate.Test/NHibernate.Test.csproj
@@ -7,9 +7,6 @@
     <NoWarn>$(NoWarn);3001;3002;3003;3005</NoWarn>
     <ContentSQLiteInteropFiles>true</ContentSQLiteInteropFiles>
   </PropertyGroup>
-  <PropertyGroup Condition="'$(TargetFramework)' == 'net461'">
-    <DefineConstants>NETFX;$(DefineConstants)</DefineConstants>
-  </PropertyGroup>
   <PropertyGroup Condition="'$(TargetFramework)' == 'netcoreapp2.0'">
     <OutputType>Exe</OutputType>
     <GenerateProgramFile>false</GenerateProgramFile>
@@ -58,7 +55,7 @@
     <PackageReference Include="FirebirdSql.Data.FirebirdClient" Version="6.3.0" />
     <PackageReference Include="Npgsql" Version="4.0.3" />
   </ItemGroup>
-  <ItemGroup Condition="'$(TargetFramework)'=='net461'">
+  <ItemGroup Condition="$(NhNetFx)">
     <Reference Include="System.Configuration" />
     <Reference Include="System.Runtime" />
     <Reference Include="System.Transactions" />
diff --git a/src/NHibernate.TestDatabaseSetup/NHibernate.TestDatabaseSetup.csproj b/src/NHibernate.TestDatabaseSetup/NHibernate.TestDatabaseSetup.csproj
index 2fff77ec8d5..f3c29432280 100644
--- a/src/NHibernate.TestDatabaseSetup/NHibernate.TestDatabaseSetup.csproj
+++ b/src/NHibernate.TestDatabaseSetup/NHibernate.TestDatabaseSetup.csproj
@@ -7,9 +7,6 @@
     <IsTestProject>true</IsTestProject>
     <NoWarn>$(NoWarn);3001;3002;3003;3005</NoWarn>
   </PropertyGroup>
-  <PropertyGroup Condition="'$(TargetFramework)' == 'net461'">
-    <DefineConstants>NETFX;$(DefineConstants)</DefineConstants>
-  </PropertyGroup>
   <PropertyGroup Condition="'$(TargetFramework)' == 'netcoreapp2.0'">
     <OutputType>Exe</OutputType>
     <GenerateProgramFile>false</GenerateProgramFile>
diff --git a/src/NHibernate/NHibernate.csproj b/src/NHibernate/NHibernate.csproj
index ebedd248ddd..ede9c97977d 100644
--- a/src/NHibernate/NHibernate.csproj
+++ b/src/NHibernate/NHibernate.csproj
@@ -14,10 +14,6 @@
     <PackageTags>ORM; O/RM; DataBase; DAL; ObjectRelationalMapping; NHibernate; ADO.Net; Core</PackageTags>
   </PropertyGroup>
   
-  <PropertyGroup Condition="'$(TargetFramework)' == 'net461'">
-    <DefineConstants>NETFX;$(DefineConstants)</DefineConstants>
-  </PropertyGroup>
-
   <ItemGroup>
     <None Remove="**\*.g" />
     <None Remove="**\*.xsd" />
@@ -45,7 +41,7 @@
     <PackageReference Include="Remotion.Linq.EagerFetching" Version="[2.2.0, 3.0)" />
   </ItemGroup>
 
-  <ItemGroup Condition="'$(TargetFramework)' == 'net461'">
+  <ItemGroup Condition="$(NhNetFx)">
     <Reference Include="System.ServiceModel" />
     <Reference Include="System.Transactions" />
     <Reference Include="System.Configuration" />