diff --git a/DigitalData.UserManager.Domain/DigitalData.UserManager.Domain.csproj b/DigitalData.UserManager.Domain/DigitalData.UserManager.Domain.csproj
index aeec329..7e0408e 100644
--- a/DigitalData.UserManager.Domain/DigitalData.UserManager.Domain.csproj
+++ b/DigitalData.UserManager.Domain/DigitalData.UserManager.Domain.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net7.0;net8.0;net9.0</TargetFrameworks>
+    <TargetFrameworks>net462;net7.0;net8.0;net9.0</TargetFrameworks>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
     <PackageId>UserManager.Domain</PackageId>
@@ -13,11 +13,38 @@
     <Copyright>Copyright 2024</Copyright>
     <PackageIcon>icon.png</PackageIcon>
     <RepositoryUrl>http://git.dd:3000/AppStd/WebUserManager.git</RepositoryUrl>
-    <PackageTags>digital data domain user maanger</PackageTags>
+    <PackageTags>digital data domain user manager</PackageTags>
     <AssemblyVersion>3.1.0</AssemblyVersion>
     <FileVersion>3.1.0</FileVersion>
   </PropertyGroup>
 
+  <PropertyGroup Condition="'$(TargetFramework)' == 'net462'">
+	<ImplicitUsings>disable</ImplicitUsings>
+	<LangVersion>7.3</LangVersion>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(TargetFramework)' != 'net462'">
+	<ImplicitUsings>enable</ImplicitUsings>
+	<LangVersion>latest</LangVersion>
+  </PropertyGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' == 'net462'">
+	<PackageReference Include="System.ComponentModel.Annotations" Version="4.7.0" />
+	<PackageReference Include="System.Drawing.Common" Version="4.7.3" />
+  </ItemGroup>
+	
+  <ItemGroup Condition="'$(TargetFramework)' == 'net7.0'">
+	  <PackageReference Include="System.Drawing.Common" Version="7.0.0" />
+  </ItemGroup>
+	
+  <ItemGroup Condition="'$(TargetFramework)' == 'net8.0'">
+	  <PackageReference Include="System.Drawing.Common" Version="8.0.16" />
+  </ItemGroup>
+	
+  <ItemGroup Condition="'$(TargetFramework)' == 'net9.0'">
+	  <PackageReference Include="System.Drawing.Common" Version="9.0.5" />
+  </ItemGroup>
+
   <ItemGroup>
     <None Include="..\Assets\icon.png">
       <Pack>True</Pack>
diff --git a/DigitalData.UserManager.Domain/Entities/BaseEntity.cs b/DigitalData.UserManager.Domain/Entities/BaseEntity.cs
index 9b59fd5..f5b57c4 100644
--- a/DigitalData.UserManager.Domain/Entities/BaseEntity.cs
+++ b/DigitalData.UserManager.Domain/Entities/BaseEntity.cs
@@ -1,6 +1,9 @@
 using System.ComponentModel;
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
+#if NETFRAMEWORK
+using System;
+#endif
 
 namespace DigitalData.UserManager.Domain.Entities
 {
@@ -13,11 +16,21 @@ namespace DigitalData.UserManager.Domain.Entities
 
         [StringLength(50)]
         [Column("ADDED_WHO")]
-        public string? AddedWho { get; set; }
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            AddedWho
+        { get; set; }
 
         [StringLength(50)]
         [Column("CHANGED_WHO")]
-        public string? ChangedWho { get; set; }
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            ChangedWho
+        { get; set; }
 
         //TODO: assign it to default value in create dto, not here!
         [Column("ADDED_WHEN", TypeName = "datetime")]
diff --git a/DigitalData.UserManager.Domain/Entities/ClientUser.cs b/DigitalData.UserManager.Domain/Entities/ClientUser.cs
index 7508416..d31e83c 100644
--- a/DigitalData.UserManager.Domain/Entities/ClientUser.cs
+++ b/DigitalData.UserManager.Domain/Entities/ClientUser.cs
@@ -1,6 +1,9 @@
 using System.ComponentModel;
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
+#if NETFRAMEWORK
+using System;
+#endif
 
 namespace DigitalData.UserManager.Domain.Entities
 {
@@ -14,18 +17,28 @@ namespace DigitalData.UserManager.Domain.Entities
 
         [Required]
         [Column("USER_ID")]
-        public int UserId { get; init; }
+        public int UserId { get; set; }
 
         [Required]
         [Column("CLIENT_ID")]
-        public int ClientId { get; init; }
+        public int ClientId { get; set; }
 
         [Column("COMMENT")]
-        public string? Comment { get; init; }
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            Comment
+        { get; set; }
 
         [StringLength(50)]
         [Column("ADDED_WHO")]
-        public string? AddedWho { get; set; }
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            AddedWho
+        { get; set; }
 
         [Column("ADDED_WHEN", TypeName = "datetime")]
         [DefaultValue("GETDATE()")]
diff --git a/DigitalData.UserManager.Domain/Entities/Group.cs b/DigitalData.UserManager.Domain/Entities/Group.cs
index 595eb56..25878d7 100644
--- a/DigitalData.UserManager.Domain/Entities/Group.cs
+++ b/DigitalData.UserManager.Domain/Entities/Group.cs
@@ -8,7 +8,11 @@ namespace DigitalData.UserManager.Domain.Entities
     public class Group : BaseEntity
     {
         [StringLength(50)]
-        public string? Name { get; set; }
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+        Name { get; set; }
 
         [Required]
         [DefaultValue(false)]
@@ -24,12 +28,17 @@ namespace DigitalData.UserManager.Domain.Entities
         public bool Active { get; set; }
 
         [StringLength(200)]
-        public string? Comment { get; set; }
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            Comment
+        { get; set; }
 
         // TODO: this column should be assigned by triggers. despite this it is not null and this is problem for creation. talk with others
         [Required]
         [Column("ECM_FK_ID")]
         [DefaultValue(-1)]
-        public int EcmFkId { get; init; } = -1;
+        public int EcmFkId { get; set; } = -1;
     }
 }
\ No newline at end of file
diff --git a/DigitalData.UserManager.Domain/Entities/GroupOfUser.cs b/DigitalData.UserManager.Domain/Entities/GroupOfUser.cs
index 0a92529..792558c 100644
--- a/DigitalData.UserManager.Domain/Entities/GroupOfUser.cs
+++ b/DigitalData.UserManager.Domain/Entities/GroupOfUser.cs
@@ -15,12 +15,24 @@ namespace DigitalData.UserManager.Domain.Entities
         public int GroupId { get; set; }
 
         [StringLength(200)]
-        public string? Comment { get; set; }
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            Comment { get; set; }
 
         [ForeignKey("UserId")]
-        public virtual User? User { get; set; }
+        public virtual User
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            User { get; set; }
 
         [ForeignKey("GroupId")]
-        public virtual Group? Group { get; set; }
+        public virtual Group
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            Group { get; set; }
     }
-}
+}
\ No newline at end of file
diff --git a/DigitalData.UserManager.Domain/Entities/Module.cs b/DigitalData.UserManager.Domain/Entities/Module.cs
index 2428cb8..15a7073 100644
--- a/DigitalData.UserManager.Domain/Entities/Module.cs
+++ b/DigitalData.UserManager.Domain/Entities/Module.cs
@@ -12,11 +12,19 @@ namespace DigitalData.UserManager.Domain.Entities
         public int Id { get; set; }
 
         [StringLength(50)]
-        public string? Name { get; set; }
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            Name { get; set; }
 
         [StringLength(20)]
         [Column("SHORT_NAME")]
-        public string? ShortName { get; set; }
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            ShortName { get; set; }
 
         #region IGNORED COLUMNS
         //[Required]
diff --git a/DigitalData.UserManager.Domain/Entities/ModuleOfUser.cs b/DigitalData.UserManager.Domain/Entities/ModuleOfUser.cs
index 85c6966..d8677dc 100644
--- a/DigitalData.UserManager.Domain/Entities/ModuleOfUser.cs
+++ b/DigitalData.UserManager.Domain/Entities/ModuleOfUser.cs
@@ -21,21 +21,41 @@ namespace DigitalData.UserManager.Domain.Entities
 
         [Column("COMMENT")]
         [StringLength(200)]
-        public string? Comment { get; set; }
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            Comment { get; set; }
 
         [Column("ADDED_WHO")]
         [StringLength(50)]
-        public string? AddedWho { get; set; } = "DEFAULT";
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            AddedWho { get; set; } = "DEFAULT";
         
         [Column("CHANGED_WHO")]
         [StringLength(50)]
-        public string? ChangedWho { get; set; }
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            ChangedWho { get; set; }
 
         [ForeignKey("UserId")]
-        public virtual User? User { get; set; }
+        public virtual User
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            User { get; set; }
 
         [ForeignKey("ModuleId")]
-        public virtual Module? Module { get; set; }
+        public virtual Module
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            Module { get; set; }
 
         #region IGNORED COLUMNS
         //public bool IsAdmin { get; set; }
@@ -53,5 +73,4 @@ namespace DigitalData.UserManager.Domain.Entities
         //public DateTime? ChangedWhen { get; set; }
         #endregion
     }
-
 }
\ No newline at end of file
diff --git a/DigitalData.UserManager.Domain/Entities/User.cs b/DigitalData.UserManager.Domain/Entities/User.cs
index 44e13bb..64d2b06 100644
--- a/DigitalData.UserManager.Domain/Entities/User.cs
+++ b/DigitalData.UserManager.Domain/Entities/User.cs
@@ -2,75 +2,101 @@
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
-namespace DigitalData.UserManager.Domain.Entities;
-
-[Table("TBDD_USER", Schema = "dbo")]
-public class User : BaseEntity
+namespace DigitalData.UserManager.Domain.Entities
 {
-    [Column("PRENAME")]
-    [StringLength(50)]
-    public string? Prename { get; set; }
+    [Table("TBDD_USER", Schema = "dbo")]
+    public class User : BaseEntity
+    {
+        [Column("PRENAME")]
+        [StringLength(50)]
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            Prename { get; set; }
 
-    [Column("NAME")]
-    [StringLength(50)]
-    public string? Name { get; set; }
+        [Column("NAME")]
+        [StringLength(50)]
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            Name { get; set; }
 
-    [Required]
-    [Column("USERNAME")]
-    [StringLength(50)]
-    public string Username { get; set; }
+        [Required]
+        [Column("USERNAME")]
+        [StringLength(50)]
+        public string Username { get; set; }
 
-    [Column("SHORTNAME")]
-    [StringLength(30)]
-    public string? Shortname { get; set; }
+        [Column("SHORTNAME")]
+        [StringLength(30)]
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            Shortname
+        { get; set; }
 
-    [Column("EMAIL")]
-    [StringLength(100)]
-    public string? Email { get; set; }
+        [Column("EMAIL")]
+        [StringLength(100)]
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            Email { get; set; }
 
-    [Required]
-    [Column("LANGUAGE")]
-    [StringLength(5)]
-    [DefaultValue("de-DE")]
-    public string Language { get; set; }
+        [Required]
+        [Column("LANGUAGE")]
+        [StringLength(5)]
+        [DefaultValue("de-DE")]
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            Language { get; set; }
 
-    [Column("COMMENT")]
-    [StringLength(500)]
-    public string? Comment { get; set; }
+        [Column("COMMENT")]
+        [StringLength(500)]
+        public string
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            Comment { get; set; }
 
-    [Column("DELETED")]
-    public bool Deleted { get; set; }
+        [Column("DELETED")]
+        public bool Deleted { get; set; }
 
-    [Required]
-    [Column("DATE_FORMAT")]
-    [StringLength(10)]
-    [DefaultValue("dd.MM.yyyy")]
-    public string DateFormat { get; set; }
+        [Required]
+        [Column("DATE_FORMAT")]
+        [StringLength(10)]
+        [DefaultValue("dd.MM.yyyy")]
+        public string DateFormat { get; set; }
 
-    [Required]
-    [Column("ACTIVE")]
-    public bool Active { get; set; }
+        [Required]
+        [Column("ACTIVE")]
+        public bool Active { get; set; }
 
-    #region IGNORED COLUMNS
-    //[Required]
-    //[Column("GENERAL_VIEWER")]
-    //[StringLength(30)]
-    //[DefaultValue("NONE")]
-    //public string GeneralViewer { get; set; }
+        #region IGNORED COLUMNS
+        //[Required]
+        //[Column("GENERAL_VIEWER")]
+        //[StringLength(30)]
+        //[DefaultValue("NONE")]
+        //public string GeneralViewer { get; set; }
 
-    //[Required]
-    //[Column("WAN_ENVIRONMENT")]
-    //public bool WanEnvironment { get; set; }
+        //[Required]
+        //[Column("WAN_ENVIRONMENT")]
+        //public bool WanEnvironment { get; set; }
 
-    //[Required]
-    //[Column("USERID_FK_INT_ECM")]
-    //public int UseridFkIntEcm { get; set; }
+        //[Required]
+        //[Column("USERID_FK_INT_ECM")]
+        //public int UseridFkIntEcm { get; set; }
 
-    //[Column("DELETED_WHEN")]
-    //public DateTime? DeletedWhen { get; set; }
+        //[Column("DELETED_WHEN")]
+        //public DateTime? DeletedWhen { get; set; }
 
-    //[Column("DELETED_WHO")]
-    //[StringLength(50)]
-    //public string? DeletedWho { get; set; }
-    #endregion
+        //[Column("DELETED_WHO")]
+        //[StringLength(50)]
+        //public string? DeletedWho { get; set; }
+        #endregion
+    }
 }
\ No newline at end of file
diff --git a/DigitalData.UserManager.Domain/Entities/UserRep.cs b/DigitalData.UserManager.Domain/Entities/UserRep.cs
index 9a4051d..cc3f6cf 100644
--- a/DigitalData.UserManager.Domain/Entities/UserRep.cs
+++ b/DigitalData.UserManager.Domain/Entities/UserRep.cs
@@ -1,5 +1,7 @@
-using System.ComponentModel.DataAnnotations;
-using System.ComponentModel.DataAnnotations.Schema;
+using System.ComponentModel.DataAnnotations.Schema;
+#if NETFRAMEWORK
+using System;
+#endif
 
 namespace DigitalData.UserManager.Domain.Entities
 {
@@ -25,15 +27,31 @@ namespace DigitalData.UserManager.Domain.Entities
         public DateTime? ValidTo { get; set; }
 
         [ForeignKey("UserId")]
-        public virtual User? User { get; set; }
+        public virtual User
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            User { get; set; }
 
         [ForeignKey("RepGroupId")]
-        public virtual Group? RepGroup { get; set; }
+        public virtual Group
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            RepGroup { get; set; }
 
         [ForeignKey("GroupId")]
-        public virtual Group? Group { get; set; }
+        public virtual Group
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            Group { get; set; }
 
         [ForeignKey("RepUserId")]
-        public virtual User? RepUser { get; set; }
+        public virtual User
+#if NET6_0_OR_GREATER
+            ?
+#endif
+            RepUser { get; set; }
     }
 }
\ No newline at end of file