diff --git a/EnvelopeGenerator.Domain/Entities/Config.cs b/EnvelopeGenerator.Domain/Entities/Config.cs
index 6c91262c..6621beb5 100644
--- a/EnvelopeGenerator.Domain/Entities/Config.cs
+++ b/EnvelopeGenerator.Domain/Entities/Config.cs
@@ -1,43 +1,41 @@
-using System.ComponentModel;
+using DigitalData.Core.Abstractions;
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_CONFIG", Schema = "dbo")]
-    public class Config
+    public class Config : IUnique<int>
     {
         [Column("DOCUMENT_PATH", TypeName = "nvarchar(256)")]
-        public string DocumentPath { get; set; }
+        public string? DocumentPath { get; init; }
 
         [Column("SENDING_PROFILE", TypeName = "int")]
         [Required]
-        [DatabaseGenerated(DatabaseGeneratedOption.None)] // Assuming SENDING_PROFILE is manually entered or controlled by the application logic
-        [DefaultValue(0)] // This sets the default value for SENDING_PROFILE
-        public int SendingProfile { get; set; }
+        public required int SendingProfile { get; init; }
 
         [Column("SIGNATURE_HOST", TypeName = "nvarchar(128)")]
-        public string SignatureHost { get; set; }
+        public string? SignatureHost { get; init; }
 
         [Column("EXTERNAL_PROGRAM_NAME", TypeName = "nvarchar(30)")]
-        public string ExternalProgramName { get; set; }
+        public string? ExternalProgramName { get; init; }
 
         [Column("EXPORT_PATH", TypeName = "nvarchar(256)")]
-        public string ExportPath { get; set; }
+        public string? ExportPath { get; init; }
 
         [Column("DOCUMENT_PATH_DMZ", TypeName = "nvarchar(512)")]
         [Required]
-        [DefaultValue("")] // This sets the default value for DOCUMENT_PATH_DMZ
-        public string DocumentPathDmz { get; set; }
+        public string? DocumentPathDmz { get; init; }
 
         [Column("EXPORT_PATH_DMZ", TypeName = "nvarchar(512)")]
         [Required]
-        [DefaultValue("")] // This sets the default value for EXPORT_PATH_DMZ
-        public string ExportPathDmz { get; set; }
+        public required string ExportPathDmz { get; init; }
 
         [Column("DOCUMENT_PATH_MOVE_AFTSEND", TypeName = "nvarchar(512)")]
         [Required]
-        [DefaultValue("")] // This sets the default value for DOCUMENT_PATH_MOVE_AFTSEND
-        public string DocumentPathMoveAftsend { get; set; }
+        public required string DocumentPathMoveAftsend { get; init; }
+
+        [Obsolete("Configuration does not have an ID; it represents a single table in the database.")]
+        public int Id => throw new InvalidOperationException("This configuration does not support an ID as it represents a single table in the database.");
     }
 }
\ No newline at end of file
diff --git a/EnvelopeGenerator.Domain/Entities/DocumentReceiverElement.cs b/EnvelopeGenerator.Domain/Entities/DocumentReceiverElement.cs
index 381b268d..6d165028 100644
--- a/EnvelopeGenerator.Domain/Entities/DocumentReceiverElement.cs
+++ b/EnvelopeGenerator.Domain/Entities/DocumentReceiverElement.cs
@@ -1,11 +1,12 @@
-using System.ComponentModel;
+using DigitalData.Core.Abstractions;
+using System.ComponentModel;
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_DOCUMENT_RECEIVER_ELEMENT", Schema = "dbo")]
-    public class DocumentReceiverElement
+    public class DocumentReceiverElement : IUnique<int>
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
diff --git a/EnvelopeGenerator.Domain/Entities/DocumentStatus.cs b/EnvelopeGenerator.Domain/Entities/DocumentStatus.cs
index 7ee87a27..dd243b76 100644
--- a/EnvelopeGenerator.Domain/Entities/DocumentStatus.cs
+++ b/EnvelopeGenerator.Domain/Entities/DocumentStatus.cs
@@ -1,10 +1,11 @@
-using System.ComponentModel.DataAnnotations;
+using DigitalData.Core.Abstractions;
+using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_DOCUMENT_STATUS", Schema = "dbo")]
-    public class DocumentStatus
+    public class DocumentStatus : IUnique<int>
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
@@ -27,7 +28,7 @@ namespace EnvelopeGenerator.Domain.Entities
         public DateTime? StatusChangedWhen { get; set; }
 
         [Column("VALUE", TypeName = "nvarchar(max)")]
-        public string Value { get; set; }
+        public string? Value { get; set; }
 
         [Required]
         [Column("ADDED_WHEN", TypeName = "datetime")]
@@ -42,4 +43,4 @@ namespace EnvelopeGenerator.Domain.Entities
         [ForeignKey("ReceiverId")]
         public virtual Receiver? Receiver { get; set; }
     }
-}
+}
\ No newline at end of file
diff --git a/EnvelopeGenerator.Domain/Entities/EmailTemplate.cs b/EnvelopeGenerator.Domain/Entities/EmailTemplate.cs
index c82f3d4e..aef2df9d 100644
--- a/EnvelopeGenerator.Domain/Entities/EmailTemplate.cs
+++ b/EnvelopeGenerator.Domain/Entities/EmailTemplate.cs
@@ -1,10 +1,11 @@
-using System.ComponentModel.DataAnnotations;
+using DigitalData.Core.Abstractions;
+using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_EMAIL_TEMPLATE", Schema = "dbo")]
-    public class EmailTemplate
+    public class EmailTemplate : IUnique<int>
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
@@ -12,12 +13,12 @@ namespace EnvelopeGenerator.Domain.Entities
         public int Id { get; set; }
 
         [Column("NAME", TypeName = "nvarchar(64)")]
-        public string Name { get; set; }
+        public string? Name { get; set; }
 
         [Column("BODY", TypeName = "nvarchar(max)")]
-        public string Body { get; set; }
+        public string? Body { get; set; }
 
         [Column("SUBJECT", TypeName = "nvarchar(512)")]
-        public string Subject { get; set; }
+        public string? Subject { get; set; }
     }
 }
\ No newline at end of file
diff --git a/EnvelopeGenerator.Domain/Entities/Envelope.cs b/EnvelopeGenerator.Domain/Entities/Envelope.cs
index b1ab8438..62f8dfd2 100644
--- a/EnvelopeGenerator.Domain/Entities/Envelope.cs
+++ b/EnvelopeGenerator.Domain/Entities/Envelope.cs
@@ -1,12 +1,12 @@
-using EnvelopeGenerator.Common;
-using EnvelopeGenerator.Common.My.Resources;
+using DigitalData.Core.Abstractions;
+using EnvelopeGenerator.Common;
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_ENVELOPE", Schema = "dbo")]
-    public class Envelope
+    public class Envelope : IUnique<int>
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
@@ -26,11 +26,11 @@ namespace EnvelopeGenerator.Domain.Entities
 
         [Required]
         [Column("ENVELOPE_UUID", TypeName = "nvarchar(36)")]
-        public string Uuid { get; set; }
+        public required string Uuid { get; init; }
 
         [Required]
         [Column("MESSAGE", TypeName = "nvarchar(max)")]
-        public string Message { get; set; }
+        public string? Message { get; set; }
 
         [Column("EXPIRES_WHEN", TypeName = "datetime")]
         public DateTime? ExpiresWhen { get; set; }
@@ -46,13 +46,13 @@ namespace EnvelopeGenerator.Domain.Entities
         public DateTime? ChangedWhen { get; set; }
 
         [Column("TITLE", TypeName = "nvarchar(128)")]
-        public string Title { get; set; }
+        public string? Title { get; set; }
 
         [Column("CONTRACT_TYPE")]
         public int? ContractType { get; set; }
 
         [Column("LANGUAGE", TypeName = "nvarchar(5)")]
-        public string Language { get; set; }
+        public required string Language { get; set; }
 
         [Column("SEND_REMINDER_EMAILS")]
         public bool? SendReminderEmails { get; set; }
diff --git a/EnvelopeGenerator.Domain/Entities/EnvelopeCertificate.cs b/EnvelopeGenerator.Domain/Entities/EnvelopeCertificate.cs
index c8bd8c6e..f6450954 100644
--- a/EnvelopeGenerator.Domain/Entities/EnvelopeCertificate.cs
+++ b/EnvelopeGenerator.Domain/Entities/EnvelopeCertificate.cs
@@ -1,10 +1,11 @@
-using System.ComponentModel.DataAnnotations;
+using DigitalData.Core.Abstractions;
+using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_ENVELOPE_CERTIFICATE", Schema = "dbo")]
-    public class EnvelopeCertificate
+    public class EnvelopeCertificate : IUnique<int>
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
@@ -17,11 +18,11 @@ namespace EnvelopeGenerator.Domain.Entities
 
         [Required]
         [Column("ENVELOPE_UUID", TypeName = "nvarchar(36)")]
-        public string EnvelopeUuid { get; set; }
+        public required string EnvelopeUuid { get; set; }
 
         [Required]
         [Column("ENVELOPE_SUBJECT", TypeName = "nvarchar(512)")]
-        public string EnvelopeSubject { get; set; }
+        public required string EnvelopeSubject { get; set; }
 
         [Required]
         [Column("CREATOR_ID")]
@@ -29,11 +30,11 @@ namespace EnvelopeGenerator.Domain.Entities
 
         [Required]
         [Column("CREATOR_NAME", TypeName = "nvarchar(128)")]
-        public string CreatorName { get; set; }
+        public required string CreatorName { get; set; }
 
         [Required]
         [Column("CREATOR_EMAIL", TypeName = "nvarchar(128)")]
-        public string CreatorEmail { get; set; }
+        public required string CreatorEmail { get; set; }
 
         [Required]
         [Column("ENVELOPE_STATUS")]
diff --git a/EnvelopeGenerator.Domain/Entities/EnvelopeDocument.cs b/EnvelopeGenerator.Domain/Entities/EnvelopeDocument.cs
index b5e64977..f90ddce2 100644
--- a/EnvelopeGenerator.Domain/Entities/EnvelopeDocument.cs
+++ b/EnvelopeGenerator.Domain/Entities/EnvelopeDocument.cs
@@ -1,10 +1,11 @@
-using System.ComponentModel.DataAnnotations;
+using DigitalData.Core.Abstractions;
+using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_ENVELOPE_DOCUMENT", Schema = "dbo")]
-    public class EnvelopeDocument
+    public class EnvelopeDocument : IUnique<int>
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
@@ -17,18 +18,18 @@ namespace EnvelopeGenerator.Domain.Entities
 
         [Required]
         [Column("FILENAME", TypeName = "nvarchar(256)")]
-        public string Filename { get; set; }
+        public required string Filename { get; set; }
 
         [Required]
         [Column("FILEPATH", TypeName = "nvarchar(256)")]
-        public string Filepath { get; set; }
+        public required string Filepath { get; set; }
 
         [Required]
         [Column("ADDED_WHEN", TypeName = "datetime")]
-        public DateTime AddedWhen { get; set; }
+        public required DateTime AddedWhen { get; set; }
 
         [Column("FILENAME_ORIGINAL", TypeName = "nvarchar(256)")]
-        public string FilenameOriginal { get; set; }
+        public required string FilenameOriginal { get; set; }
 
         public IEnumerable<DocumentReceiverElement>? Elements { get; set; }
     }
diff --git a/EnvelopeGenerator.Domain/Entities/EnvelopeHistory.cs b/EnvelopeGenerator.Domain/Entities/EnvelopeHistory.cs
index d03922fd..ef9f33be 100644
--- a/EnvelopeGenerator.Domain/Entities/EnvelopeHistory.cs
+++ b/EnvelopeGenerator.Domain/Entities/EnvelopeHistory.cs
@@ -1,4 +1,5 @@
-using DigitalData.UserManager.Domain.Entities;
+using DigitalData.Core.Abstractions;
+using DigitalData.UserManager.Domain.Entities;
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 using static EnvelopeGenerator.Common.Constants;
@@ -6,7 +7,7 @@ using static EnvelopeGenerator.Common.Constants;
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_ENVELOPE_HISTORY", Schema = "dbo")]
-    public class EnvelopeHistory
+    public class EnvelopeHistory : IUnique<long>
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
diff --git a/EnvelopeGenerator.Domain/Entities/EnvelopeReceiverBase.cs b/EnvelopeGenerator.Domain/Entities/EnvelopeReceiverBase.cs
index 7669389d..ef934a19 100644
--- a/EnvelopeGenerator.Domain/Entities/EnvelopeReceiverBase.cs
+++ b/EnvelopeGenerator.Domain/Entities/EnvelopeReceiverBase.cs
@@ -1,10 +1,11 @@
-using System.ComponentModel.DataAnnotations;
+using DigitalData.Core.Abstractions;
+using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_ENVELOPE_RECEIVER", Schema = "dbo")]
-    public class EnvelopeReceiverBase
+    public class EnvelopeReceiverBase : IUnique<(int Envelope, int Receiver)>
     {
         [Key]
         [Column("ENVELOPE_ID")]
@@ -39,5 +40,7 @@ namespace EnvelopeGenerator.Domain.Entities
 
         [Column("CHANGED_WHEN", TypeName = "datetime")]
         public DateTime? ChangedWhen { get; set; }
+
+        public (int Envelope, int Receiver) Id => (Envelope: EnvelopeId, Receiver: ReceiverId);
     }
 }
\ No newline at end of file
diff --git a/EnvelopeGenerator.Domain/Entities/EnvelopeType.cs b/EnvelopeGenerator.Domain/Entities/EnvelopeType.cs
index c1684672..bd837e81 100644
--- a/EnvelopeGenerator.Domain/Entities/EnvelopeType.cs
+++ b/EnvelopeGenerator.Domain/Entities/EnvelopeType.cs
@@ -1,12 +1,11 @@
-using System;
+using DigitalData.Core.Abstractions;
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
-using EnvelopeGenerator.Domain.Entities;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_ENVELOPE_TYPE", Schema = "dbo")]
-    public class EnvelopeType
+    public class EnvelopeType : IUnique<int>
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
@@ -15,10 +14,10 @@ namespace EnvelopeGenerator.Domain.Entities
 
         [Required]
         [Column("TITLE", TypeName = "nvarchar(128)")]
-        public string Title { get; set; }
+        public required string Title { get; set; }
 
         [Column("LANGUAGE", TypeName = "nvarchar(5)")]
-        public string Language { get; set; }
+        public string? Language { get; set; }
 
         [Column("EXPIRES_DAYS")]
         public int? ExpiresDays { get; set; }
diff --git a/EnvelopeGenerator.Domain/Entities/Receiver.cs b/EnvelopeGenerator.Domain/Entities/Receiver.cs
index ce354483..ae39daf4 100644
--- a/EnvelopeGenerator.Domain/Entities/Receiver.cs
+++ b/EnvelopeGenerator.Domain/Entities/Receiver.cs
@@ -1,10 +1,11 @@
-using System.ComponentModel.DataAnnotations;
+using DigitalData.Core.Abstractions;
+using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_RECEIVER", Schema = "dbo")]
-    public class Receiver
+    public class Receiver : IUnique<int>
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
diff --git a/EnvelopeGenerator.Domain/Entities/UserReceiver.cs b/EnvelopeGenerator.Domain/Entities/UserReceiver.cs
index 9b221297..c2fc7c0c 100644
--- a/EnvelopeGenerator.Domain/Entities/UserReceiver.cs
+++ b/EnvelopeGenerator.Domain/Entities/UserReceiver.cs
@@ -1,10 +1,11 @@
-using System.ComponentModel.DataAnnotations;
+using DigitalData.Core.Abstractions;
+using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_USER_RECEIVER", Schema = "dbo")]
-    public class UserReceiver
+    public class UserReceiver : IUnique<int>
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
@@ -21,16 +22,16 @@ namespace EnvelopeGenerator.Domain.Entities
 
         [Required]
         [Column("NAME", TypeName = "nvarchar(128)")]
-        public string Name { get; set; }
+        public required string Name { get; set; }
 
         [Column("COMPANY_NAME", TypeName = "nvarchar(128)")]
-        public string CompanyName { get; set; }
+        public string? CompanyName { get; set; }
 
         [Column("JOB_TITLE", TypeName = "nvarchar(128)")]
-        public string JobTitle { get; set; }
+        public string? JobTitle { get; set; }
 
         [Required]
         [Column("ADDED_WHEN", TypeName = "datetime")]
-        public DateTime AddedWhen { get; set; }
+        public required DateTime AddedWhen { get; init; }
     }
 }
\ No newline at end of file
diff --git a/EnvelopeGenerator.Domain/EnvelopeGenerator.Domain.csproj b/EnvelopeGenerator.Domain/EnvelopeGenerator.Domain.csproj
index 40acf713..3480802f 100644
--- a/EnvelopeGenerator.Domain/EnvelopeGenerator.Domain.csproj
+++ b/EnvelopeGenerator.Domain/EnvelopeGenerator.Domain.csproj
@@ -7,6 +7,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="DigitalData.Core.Abstractions" Version="2.0.0" />
     <PackageReference Include="DigitalData.EmailProfilerDispatcher.Abstraction" Version="1.0.0" />
     <PackageReference Include="UserManager.Domain" Version="1.0.0" />
   </ItemGroup>
diff --git a/EnvelopeGenerator.Infrastructure/EnvelopeGenerator.Infrastructure.csproj b/EnvelopeGenerator.Infrastructure/EnvelopeGenerator.Infrastructure.csproj
index f81afd68..42b215a8 100644
--- a/EnvelopeGenerator.Infrastructure/EnvelopeGenerator.Infrastructure.csproj
+++ b/EnvelopeGenerator.Infrastructure/EnvelopeGenerator.Infrastructure.csproj
@@ -7,8 +7,8 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="DigitalData.Core.Abstractions" Version="1.0.1.1" />
-    <PackageReference Include="DigitalData.Core.Infrastructure" Version="1.0.1.1" />
+    <PackageReference Include="DigitalData.Core.Abstractions" Version="2.0.0" />
+    <PackageReference Include="DigitalData.Core.Infrastructure" Version="2.0.0" />
     <PackageReference Include="Microsoft.EntityFrameworkCore" Version="7.0.16" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="7.0.15">
       <PrivateAssets>all</PrivateAssets>
diff --git a/EnvelopeGenerator.Infrastructure/Repositories/UserReceiverRepository.cs b/EnvelopeGenerator.Infrastructure/Repositories/UserReceiverRepository.cs
index 2c5800ec..fbbb575d 100644
--- a/EnvelopeGenerator.Infrastructure/Repositories/UserReceiverRepository.cs
+++ b/EnvelopeGenerator.Infrastructure/Repositories/UserReceiverRepository.cs
@@ -1,5 +1,4 @@
 using DigitalData.Core.Infrastructure;
-using DigitalData.UserManager.Infrastructure.Repositories;
 using EnvelopeGenerator.Domain.Entities;
 using EnvelopeGenerator.Infrastructure.Contracts;