Refactor using directives and add User entity

- Updated `using` directives in `Config.cs` and `EnvelopeType.cs` to include additional namespaces and removed `DigitalData.Core.Abstractions`.
- Adjusted formatting for `StatusName` and `IsAlreadySent` properties in `Envelope.cs` for consistency.
- Simplified `User` property in `Envelope.cs` by removing the namespace prefix.
- Introduced a new `User` class in `User.cs` with various properties and data annotations for database mapping.
- Removed the `<Nullable>` property from `EnvelopeGenerator.Domain.csproj`, which may impact nullability handling.

EnvelopeGenerator.Application/DTOs/ConfigDto.cs

@@ -3,19 +3,45 @@ using Microsoft.AspNetCore.Mvc;
 using System.ComponentModel.DataAnnotations.Schema;
 using System.Text.Json.Serialization;
 
-namespace EnvelopeGenerator.Application.DTOs
+namespace EnvelopeGenerator.Application.DTOs;
+
+/// <summary>
+/// Data Transfer Object representing configuration settings.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class ConfigDto : IUnique<int>
 {
-    [ApiExplorerSettings(IgnoreApi = true)]
+    /// <summary>
-    public record ConfigDto(
+    /// Gets or sets the path to the document.
-        string DocumentPath,
+    /// </summary>
-        int SendingProfile,
+    public string DocumentPath { get; set; }
-        string SignatureHost,
+
-        string ExternalProgramName,
+    /// <summary>
-        string ExportPath) : IUnique<int>
+    /// Gets or sets the sending profile identifier.
-    {
+    /// </summary>
-        [NotMapped]
+    public int SendingProfile { get; set; }
-        [JsonIgnore]
+
-        [Obsolete("Configuration does not have an ID; it represents a single table in the database.")]
+    /// <summary>
-        public int Id => throw new InvalidOperationException("This configuration does not support an ID as it represents a single row in the database.");
+    /// Gets or sets the signature host URL or name.
-    };
+    /// </summary>
+    public string SignatureHost { get; set; }
+
+    /// <summary>
+    /// Gets or sets the name of the external program.
+    /// </summary>
+    public string ExternalProgramName { get; set; }
+
+    /// <summary>
+    /// Gets or sets the path where exports will be saved.
+    /// </summary>
+    public string ExportPath { get; set; }
+
+    /// <summary>
+    /// Gets the ID of the configuration.
+    /// This DTO represents a single row in the database and does not support an ID.
+    /// </summary>
+    [NotMapped]
+    [JsonIgnore]
+    [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 row in the database.");
 }

EnvelopeGenerator.Application/DTOs/DocumentReceiverElementDto.cs

@@ -1,26 +1,96 @@
 using DigitalData.Core.Abstractions;
 using Microsoft.AspNetCore.Mvc;
 
-namespace EnvelopeGenerator.Application.DTOs
+namespace EnvelopeGenerator.Application.DTOs;
+
+/// <summary>
+/// Data Transfer Object representing a positioned element assigned to a document receiver.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class DocumentReceiverElementDto : IUnique<int>
 {
-    [ApiExplorerSettings(IgnoreApi = true)]
+    /// <summary>
-    public record DocumentReceiverElementDto(
+    /// Gets or sets the unique identifier of the element.
-        int Id,
+    /// </summary>
-        int DocumentId,
+    public int Id { get; set; }
-        int ReceiverId,
+
-        int ElementType,
+    /// <summary>
-        double X,
+    /// Gets or sets the identifier of the associated document.
-        double Y,
+    /// </summary>
-        double Width,
+    public int DocumentId { get; set; }
-        double Height,
+
-        int Page,
+    /// <summary>
-        bool Required,
+    /// Gets or sets the identifier of the receiver.
-        string? Tooltip,
+    /// </summary>
-        bool ReadOnly,
+    public int ReceiverId { get; set; }
-        int AnnotationIndex,
+
-        DateTime AddedWhen,
+    /// <summary>
-        DateTime? ChangedWhen,
+    /// Gets or sets the type of the element.
-        double Top,
+    /// </summary>
-        double Left
+    public int ElementType { get; set; }
-        ): IUnique<int>;
+
+    /// <summary>
+    /// Gets or sets the X coordinate of the element.
+    /// </summary>
+    public double X { get; set; }
+
+    /// <summary>
+    /// Gets or sets the Y coordinate of the element.
+    /// </summary>
+    public double Y { get; set; }
+
+    /// <summary>
+    /// Gets or sets the width of the element.
+    /// </summary>
+    public double Width { get; set; }
+
+    /// <summary>
+    /// Gets or sets the height of the element.
+    /// </summary>
+    public double Height { get; set; }
+
+    /// <summary>
+    /// Gets or sets the page number where the element appears.
+    /// </summary>
+    public int Page { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether the element is required.
+    /// </summary>
+    public bool Required { get; set; }
+
+    /// <summary>
+    /// Gets or sets the tooltip text for the element.
+    /// </summary>
+    public string? Tooltip { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether the element is read-only.
+    /// </summary>
+    public bool ReadOnly { get; set; }
+
+    /// <summary>
+    /// Gets or sets the annotation index for ordering or reference.
+    /// </summary>
+    public int AnnotationIndex { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when the element was added.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when the element was last changed, if applicable.
+    /// </summary>
+    public DateTime? ChangedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the top position of the element (in layout terms).
+    /// </summary>
+    public double Top { get; set; }
+
+    /// <summary>
+    /// Gets or sets the left position of the element (in layout terms).
+    /// </summary>
+    public double Left { get; set; }
 }

EnvelopeGenerator.Application/DTOs/DocumentStatusDto.cs

@@ -1,18 +1,51 @@
 using DigitalData.Core.Abstractions;
 using Microsoft.AspNetCore.Mvc;
 
-namespace EnvelopeGenerator.Application.DTOs
+namespace EnvelopeGenerator.Application.DTOs;
+
+/// <summary>
+/// Data Transfer Object representing the status of a document for a specific receiver.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class DocumentStatusDto : IUnique<int>
 {
-    [ApiExplorerSettings(IgnoreApi = true)]
+    /// <summary>
-    public record DocumentStatusDto(
+    /// Gets or sets the unique identifier of the document status entry.
-        int Id,
+    /// </summary>
-        int EnvelopeId,
+    public int Id { get; set; }
-        int ReceiverId,
+
-        int Status,
+    /// <summary>
-        DateTime? StatusChangedWhen,
+    /// Gets or sets the ID of the associated envelope.
-        DateTime AddedWhen,
+    /// </summary>
-        DateTime? ChangedWhen) : IUnique<int>
+    public int EnvelopeId { get; set; }
-    {
+
-        public string? Value { get; set; }
+    /// <summary>
-    };
+    /// Gets or sets the ID of the receiver associated with this status.
+    /// </summary>
+    public int ReceiverId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the current status code.
+    /// </summary>
+    public int Status { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when the status was changed.
+    /// </summary>
+    public DateTime? StatusChangedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when this record was added.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when this record was last changed.
+    /// </summary>
+    public DateTime? ChangedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the display value associated with the status.
+    /// </summary>
+    public string? Value { get; set; }
 }

EnvelopeGenerator.Application/DTOs/EnvelopeCertificateDto.cs

@@ -1,16 +1,51 @@
 using DigitalData.Core.Abstractions;
 using Microsoft.AspNetCore.Mvc;
 
-namespace EnvelopeGenerator.Application.DTOs
+namespace EnvelopeGenerator.Application.DTOs;
+
+/// <summary>
+/// Data Transfer Object representing certificate information for an envelope.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class EnvelopeCertificateDto : IUnique<int>
 {
-    [ApiExplorerSettings(IgnoreApi = true)]
+    /// <summary>
-    public record EnvelopeCertificateDto(
+    /// Gets the unique identifier of the certificate.
-        int Id,
+    /// </summary>
-        int EnvelopeId,
+    public int Id { get; init; }
-        string EnvelopeUuid,
+
-        string EnvelopeSubject,
+    /// <summary>
-        int CreatorId,
+    /// Gets the envelope ID associated with the certificate.
-        string CreatorName,
+    /// </summary>
-        string CreatorEmail,
+    public int EnvelopeId { get; init; }
-        int EnvelopeStatus) : IUnique<int>;
+
+    /// <summary>
+    /// Gets the UUID of the envelope.
+    /// </summary>
+    public string EnvelopeUuid { get; init; }
+
+    /// <summary>
+    /// Gets the subject of the envelope.
+    /// </summary>
+    public string EnvelopeSubject { get; init; }
+
+    /// <summary>
+    /// Gets the ID of the creator of the envelope.
+    /// </summary>
+    public int CreatorId { get; init; }
+
+    /// <summary>
+    /// Gets the name of the creator.
+    /// </summary>
+    public string CreatorName { get; init; }
+
+    /// <summary>
+    /// Gets the email address of the creator.
+    /// </summary>
+    public string CreatorEmail { get; init; }
+
+    /// <summary>
+    /// Gets the current status of the envelope.
+    /// </summary>
+    public int EnvelopeStatus { get; init; }
 }

EnvelopeGenerator.Application/DTOs/EnvelopeDocumentDto.cs

@@ -1,15 +1,36 @@
 using DigitalData.Core.Abstractions;
 using Microsoft.AspNetCore.Mvc;
 
-namespace EnvelopeGenerator.Application.DTOs
+namespace EnvelopeGenerator.Application.DTOs;
+
+/// <summary>
+/// Data Transfer Object representing a document within an envelope, including optional binary data and form elements.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class EnvelopeDocumentDto : IUnique<int>
 {
-    [ApiExplorerSettings(IgnoreApi = true)]
+    /// <summary>
-    public record EnvelopeDocumentDto
+    /// Gets or sets the unique identifier of the document.
-    (
+    /// </summary>
-        int Id,
+    public int Id { get; set; }
-        int EnvelopeId,
+
-        DateTime AddedWhen,
+    /// <summary>
-        byte[]? ByteData = null,
+    /// Gets or sets the envelope ID to which the document belongs.
-        IEnumerable<DocumentReceiverElementDto>? Elements = null
+    /// </summary>
-    ) : IUnique<int>;
+    public int EnvelopeId { get; set; }
-}
+
+    /// <summary>
+    /// Gets or sets the date and time when the document was added.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the binary data of the document, if available.
+    /// </summary>
+    public byte[]? ByteData { get; set; }
+
+    /// <summary>
+    /// Gets or sets the collection of elements associated with the document for receiver interactions, if any.
+    /// </summary>
+    public IEnumerable<DocumentReceiverElementDto>? Elements { get; set; }
+}

EnvelopeGenerator.Application/DTOs/EnvelopeDto.cs

@@ -4,53 +4,52 @@ using DigitalData.UserManager.Application.DTOs.User;
 using EnvelopeGenerator.Domain.Entities;
 using Microsoft.AspNetCore.Mvc;
 
-namespace EnvelopeGenerator.Application.DTOs
+namespace EnvelopeGenerator.Application.DTOs;
+
+[ApiExplorerSettings(IgnoreApi = true)]
+public record EnvelopeDto : IUnique<int>
 {
-    [ApiExplorerSettings(IgnoreApi = true)]
+	public int Id { get; set; }
-    public record EnvelopeDto() : IUnique<int>
-    {
-		public int Id { get; set; }
 
-		public int UserId { get; set; }
+	public int UserId { get; set; }
 
-		public int Status { get; set; }
+	public int Status { get; set; }
 
-		public string StatusName { get; set; }
+	public string StatusName { get; set; }
 
-        public string Uuid { get; set; }
+    public string Uuid { get; set; }
 
-		[TemplatePlaceholder("[MESSAGE]")]
+	[TemplatePlaceholder("[MESSAGE]")]
-		public string Message { get; set; }
+	public string Message { get; set; }
 
-		public DateTime AddedWhen { get; set; }
+	public DateTime AddedWhen { get; set; }
 
-		public DateTime? ChangedWhen { get; set; }
+	public DateTime? ChangedWhen { get; set; }
 
-		[TemplatePlaceholder("[DOCUMENT_TITLE]")]
+	[TemplatePlaceholder("[DOCUMENT_TITLE]")]
-		public string Title { get; set; }
+	public string Title { get; set; }
 
-		public int? ContractType { get; set; }
+	public int? ContractType { get; set; }
 
-		public string Language { get; set; }
+	public string Language { get; set; }
 
-		public int? EnvelopeTypeId { get; set; }
+	public int? EnvelopeTypeId { get; set; }
 
-		public int? CertificationType { get; set; }
+	public int? CertificationType { get; set; }
 
-		public bool? UseAccessCode { get; set; }
+	public bool? UseAccessCode { get; set; }
 
-        public bool TFAEnabled { get; init; }
+    public bool TFAEnabled { get; init; }
 
-		public UserReadDto? User { get; set; }
+	public UserReadDto? User { get; set; }
 
-		public EnvelopeType? EnvelopeType { get; set; }
+	public EnvelopeType? EnvelopeType { get; set; }
 
-		public string? EnvelopeTypeTitle { get; set; }
+	public string? EnvelopeTypeTitle { get; set; }
 
-		public bool IsAlreadySent { get; set; }
+	public bool IsAlreadySent { get; set; }
 
-        public byte[]? DocResult { get; init; }
+    public byte[]? DocResult { get; init; }
 
-        public IEnumerable<EnvelopeDocumentDto>? Documents { get; set; }
+    public IEnumerable<EnvelopeDocumentDto>? Documents { get; set; }
-	}
 }

EnvelopeGenerator.Application/DTOs/EnvelopeHistory/EnvelopeHistoryCreateDto.cs

@@ -1,12 +1,34 @@
 using Microsoft.AspNetCore.Mvc;
 
-namespace EnvelopeGenerator.Application.DTOs.EnvelopeHistory
+namespace EnvelopeGenerator.Application.DTOs.EnvelopeHistory;
+
+/// <summary>
+/// Data Transfer Object for creating a new envelope history record.
+/// </summary>
+public class EnvelopeHistoryCreateDto
 {
-    [ApiExplorerSettings(IgnoreApi = true)]
+    /// <summary>
-    public record EnvelopeHistoryCreateDto(
+    /// Gets or sets the identifier of the envelope.
-        int EnvelopeId,
+    /// </summary>
-        string UserReference,
+    public int EnvelopeId { get; set; }
-        int Status,
+
-        DateTime? ActionDate,
+    /// <summary>
-        string? Comment = null);
+    /// Gets or sets the user reference associated with the action.
+    /// </summary>
+    public required string UserReference { get; set; }
+
+    /// <summary>
+    /// Gets or sets the status of the envelope at the time of the action.
+    /// </summary>
+    public int Status { get; set; }
+
+    /// <summary>
+    /// Gets or sets the date and time when the action occurred.
+    /// </summary>
+    public DateTime? ActionDate { get; set; }
+
+    /// <summary>
+    /// Gets or sets an optional comment related to the action.
+    /// </summary>
+    public string? Comment { get; set; }
 }

EnvelopeGenerator.Application/DTOs/EnvelopeHistory/EnvelopeHistoryDto.cs

@@ -1,36 +1,73 @@
 using DigitalData.Core.Abstractions;
-using DigitalData.Core.DTO;
 using DigitalData.UserManager.Application.DTOs.User;
 using EnvelopeGenerator.Application.DTOs.Receiver;
-using Microsoft.AspNetCore.Mvc;
 using static EnvelopeGenerator.Common.Constants;
 
 namespace EnvelopeGenerator.Application.DTOs.EnvelopeHistory;
 
 /// <summary>
-/// 
+/// Data Transfer Object representing the history of an envelope, including status, sender, receiver, and related metadata.
 /// </summary>
-/// <param name="Id"></param>
+public record EnvelopeHistoryDto : IUnique<long>
-/// <param name="EnvelopeId"></param>
+{
-/// <param name="UserReference"></param>
+    /// <summary>
-/// <param name="Status"></param>
+    /// Unique identifier for the envelope history entry.
-/// <param name="StatusName"></param>
+    /// </summary>
-/// <param name="AddedWhen"></param>
+    public long Id { get; set; }
-/// <param name="ActionDate"></param>
+
-/// <param name="Sender"></param>
+    /// <summary>
-/// <param name="Receiver"></param>
+    /// Identifier of the associated envelope.
-/// <param name="ReferenceType"></param>
+    /// </summary>
-/// <param name="Comment"></param>
+    public int EnvelopeId { get; set; }
-[ApiExplorerSettings(IgnoreApi = true)]
+
-public record EnvelopeHistoryDto(
+    /// <summary>
-    long Id,
+    /// Reference string for the user related to this history entry.
-    int EnvelopeId,
+    /// </summary>
-    string UserReference,
+    public string UserReference { get; set; }
-    int Status,
+
-    string? StatusName,
+    /// <summary>
-    DateTime AddedWhen,
+    /// Status code of the envelope at this history point.
-    DateTime? ActionDate,
+    /// </summary>
-    UserCreateDto? Sender,
+    public int Status { get; set; }
-    ReceiverReadDto? Receiver,
+
-    ReferenceType ReferenceType,
+    /// <summary>
-    string? Comment = null) : BaseDTO<long>(Id), IUnique<long>;
+    /// Human-readable name of the status.
+    /// </summary>
+    public string? StatusName { get; set; }
+
+    /// <summary>
+    /// Date and time when this history entry was added.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// Date and time when an action was performed, if applicable.
+    /// </summary>
+    public DateTime? ActionDate { get; set; }
+
+    /// <summary>
+    /// Information about the sender associated with this history entry.
+    /// </summary>
+    public UserCreateDto? Sender { get; set; }
+
+    /// <summary>
+    /// Information about the receiver associated with this history entry.
+    /// </summary>
+    public ReceiverReadDto? Receiver { get; set; }
+
+    /// <summary>
+    /// Type of reference for this history entry.
+    /// </summary>
+    public ReferenceType ReferenceType { get; set; }
+
+    /// <summary>
+    /// Optional comment related to this history entry.
+    /// </summary>
+    public string? Comment { get; set; }
+
+    /// <inheritdoc/>
+    public override int GetHashCode()
+    {
+        return Id.GetHashCode();
+    }
+};

EnvelopeGenerator.Application/DTOs/EnvelopeReceiverReadOnly/EnvelopeReceiverReadOnlyDto.cs

@@ -1,18 +1,62 @@
 using EnvelopeGenerator.Application.DTOs.Receiver;
 using Microsoft.AspNetCore.Mvc;
 
-namespace EnvelopeGenerator.Application.DTOs.EnvelopeReceiverReadOnly
+namespace EnvelopeGenerator.Application.DTOs.EnvelopeReceiverReadOnly;
+
+/// <summary>
+/// Represents a read-only Data Transfer Object (DTO) for an envelope receiver.
+/// Contains information about the receiver, associated envelope, and audit details.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class EnvelopeReceiverReadOnlyDto
 {
-    [ApiExplorerSettings(IgnoreApi = true)]
+    /// <summary>
-    public record EnvelopeReceiverReadOnlyDto(
+    /// Gets or inits the unique identifier of the envelope receiver.
-        long Id,
+    /// </summary>
-        long EnvelopeId,
+    public long Id { get; init; }
-        string ReceiverMail,
+
-        DateTime DateValid,
+    /// <summary>
-        DateTime AddedWhen,
+    /// Gets or inits the identifier of the associated envelope.
-        string AddedWho,
+    /// </summary>
-        EnvelopeDto? Envelope = null,              
+    public long EnvelopeId { get; init; }
-        string? ChangedWho = null,
+
-        DateTime? ChangedWhen = null,
+    /// <summary>
-        ReceiverReadDto? Receiver = null);
+    /// Gets or inits the email address of the receiver.
+    /// </summary>
+    public string ReceiverMail { get; set; }
+
+    /// <summary>
+    /// Gets or inits the date until which the receiver is valid.
+    /// </summary>
+    public DateTime DateValid { get; set; }
+
+    /// <summary>
+    /// Gets or inits the date and time when the receiver was added.
+    /// </summary>
+    public DateTime AddedWhen { get; init; }
+
+    /// <summary>
+    /// Gets or inits the user who added the receiver.
+    /// </summary>
+    public string AddedWho { get; init; }
+
+    /// <summary>
+    /// Gets or inits the associated envelope details.
+    /// </summary>
+    public EnvelopeDto? Envelope { get; set; }
+
+    /// <summary>
+    /// Gets or inits the user who last changed the receiver, if any.
+    /// </summary>
+    public string? ChangedWho { get; set; }
+
+    /// <summary>
+    /// Gets or inits the date and time when the receiver was last changed, if any.
+    /// </summary>
+    public DateTime? ChangedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or inits the associated receiver details.
+    /// </summary>
+    public ReceiverReadDto? Receiver { get; set; }
 }

EnvelopeGenerator.Application/DTOs/EnvelopeReceiverReadOnly/EnvelopeReceiverReadOnlyUpdateDto.cs

@@ -1,14 +1,31 @@
 using DigitalData.Core.Abstractions;
 using Microsoft.AspNetCore.Mvc;
 
-namespace EnvelopeGenerator.Application.DTOs.EnvelopeReceiverReadOnly
+namespace EnvelopeGenerator.Application.DTOs.EnvelopeReceiverReadOnly;
+
+/// <summary>
+/// Data Transfer Object for updating a read-only envelope receiver.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class EnvelopeReceiverReadOnlyUpdateDto : IUnique<long>
 {
-    [ApiExplorerSettings(IgnoreApi = true)]
+    /// <summary>
-    public record EnvelopeReceiverReadOnlyUpdateDto(
+    /// Gets or sets the unique identifier of the envelope receiver.
-        long Id,
+    /// </summary>
-        DateTime DateValid,
+    public long Id { get; init; }
-        string ChangedWho) : IUnique<long>
+
-    {
+    /// <summary>
-        public DateTime ChangedWhen { get; } = DateTime.Now;
+    /// Gets or sets the date when the envelope receiver becomes valid.
-    };
+    /// </summary>
+    public DateTime DateValid { get; set; }
+
+    /// <summary>
+    /// Gets or sets the name of the user who made the change.
+    /// </summary>
+    public string ChangedWho { get; set; }
+
+    /// <summary>
+    /// Gets or sets the date and time when the change was made.
+    /// </summary>
+    public DateTime ChangedWhen { get; set; } = DateTime.Now;
 }

EnvelopeGenerator.Application/DTOs/EnvelopeTypeDto.cs

@@ -1,23 +1,86 @@
 using DigitalData.Core.Abstractions;
 using Microsoft.AspNetCore.Mvc;
 
-namespace EnvelopeGenerator.Application.DTOs
+namespace EnvelopeGenerator.Application.DTOs;
+
+/// <summary>
+/// Data Transfer Object representing a type of envelope with its configuration settings.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class EnvelopeTypeDto : IUnique<int>
 {
-    [ApiExplorerSettings(IgnoreApi = true)]
+    /// <summary>
-    public record EnvelopeTypeDto(
+    /// Gets or sets the unique identifier of the envelope type.
-        int Id,
+    /// </summary>
-        string Title,
+    public int Id { get; set; }
-        string Language,
+
-        int? ExpiresDays,
+    /// <summary>
-        int? CertificationType,
+    /// Gets or sets the title of the envelope type.
-        bool? UseAccessCode,
+    /// </summary>
-        int? FinalEmailToCreator,
+    public string Title { get; set; }
-        int? FinalEmailToReceivers,
+
-        DateTime AddedWhen,
+    /// <summary>
-        DateTime? ChangedWhen,
+    /// Gets or sets the language code used in this envelope type.
-        int? ExpiresWarningDays,
+    /// </summary>
-        bool? SendReminderEmails,
+    public string Language { get; set; }
-        int? FirstReminderDays,
+
-        int? ReminderIntervalDays,
+    /// <summary>
-        int? ContractType) : IUnique<int>;
+    /// Gets or sets the number of days after which the envelope expires.
+    /// </summary>
+    public int? ExpiresDays { get; set; }
+
+    /// <summary>
+    /// Gets or sets the certification type identifier.
+    /// </summary>
+    public int? CertificationType { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether an access code is required.
+    /// </summary>
+    public bool? UseAccessCode { get; set; }
+
+    /// <summary>
+    /// Gets or sets the final email template ID to be sent to the creator.
+    /// </summary>
+    public int? FinalEmailToCreator { get; set; }
+
+    /// <summary>
+    /// Gets or sets the final email template ID to be sent to the receivers.
+    /// </summary>
+    public int? FinalEmailToReceivers { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when this envelope type was added.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when this envelope type was last changed.
+    /// </summary>
+    public DateTime? ChangedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the number of days before expiry when a warning should be sent.
+    /// </summary>
+    public int? ExpiresWarningDays { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether reminder emails should be sent.
+    /// </summary>
+    public bool? SendReminderEmails { get; set; }
+
+    /// <summary>
+    /// Gets or sets the number of days before the first reminder is sent.
+    /// </summary>
+    public int? FirstReminderDays { get; set; }
+
+    /// <summary>
+    /// Gets or sets the interval in days between reminder emails.
+    /// </summary>
+    public int? ReminderIntervalDays { get; set; }
+
+    /// <summary>
+    /// Gets or sets the contract type associated with the envelope type.
+    /// </summary>
+    public int? ContractType { get; set; }
 }

EnvelopeGenerator.Application/DTOs/Receiver/ReceiverCreateDto.cs

@@ -3,21 +3,30 @@ using System.ComponentModel.DataAnnotations;
 using System.Security.Cryptography;
 using System.Text;
 
-namespace EnvelopeGenerator.Application.DTOs.Receiver
+namespace EnvelopeGenerator.Application.DTOs.Receiver;
-{
-    [ApiExplorerSettings(IgnoreApi = true)]
-    public record ReceiverCreateDto([EmailAddress] string EmailAddress, string? TotpSecretkey = null)
-    {
-        public string Signature => sha256HexOfMail.Value;
 
-        private readonly Lazy<string> sha256HexOfMail = new(() =>
+[ApiExplorerSettings(IgnoreApi = true)]
+public record ReceiverCreateDto
+{
+    public ReceiverCreateDto()
+    {
+        _sha256HexOfMail = new(() =>
         {
             var bytes_arr = Encoding.UTF8.GetBytes(EmailAddress.ToUpper());
             var hash_arr = SHA256.HashData(bytes_arr);
             var hexa_str = BitConverter.ToString(hash_arr);
             return hexa_str.Replace("-", string.Empty);
         });
+    }
 
-        public DateTime AddedWhen { get; } = DateTime.Now;
+    [EmailAddress]
-    };
+    public required string EmailAddress { get; init; }
-}
+
+    public string? TotpSecretkey { get; init; }
+
+    public string Signature => _sha256HexOfMail.Value;
+
+    private readonly Lazy<string> _sha256HexOfMail;
+
+    public DateTime AddedWhen { get; } = DateTime.Now;
+};

EnvelopeGenerator.Application/DTOs/Receiver/ReceiverReadDto.cs

@@ -1,5 +1,4 @@
 using DigitalData.Core.Abstractions;
-using DigitalData.Core.DTO;
 using EnvelopeGenerator.Application.DTOs.EnvelopeReceiver;
 using Microsoft.AspNetCore.Mvc;
 using System.Text.Json.Serialization;
@@ -7,19 +6,27 @@ using System.Text.Json.Serialization;
 namespace EnvelopeGenerator.Application.DTOs.Receiver;
 
 [ApiExplorerSettings(IgnoreApi = true)]
-public record ReceiverReadDto(
+public class ReceiverReadDto : IUnique<int>
-    int Id,
-    string EmailAddress,
-    string Signature,
-    DateTime AddedWhen
-    ) : BaseDTO<int>(Id), IUnique<int>
 {
+    public int Id { get; set; }
+
+    public string EmailAddress { get; set; }
+
+    public string Signature { get; set; }
+
+    public DateTime AddedWhen { get; set; }
+
     [JsonIgnore]
-    public IEnumerable<EnvelopeReceiverBasicDto>? EnvelopeReceivers { get; init; }
+    public IEnumerable<EnvelopeReceiverBasicDto>? EnvelopeReceivers { get; set; }
 
     public string? LastUsedName => EnvelopeReceivers?.LastOrDefault()?.Name;
 
     public string? TotpSecretkey { get; set; } = null;
 
     public DateTime? TfaRegDeadline { get; set; }
-};
+
+    public override int GetHashCode()
+    {
+        return Id.GetHashCode();
+    }
+}

EnvelopeGenerator.Application/DTOs/Receiver/ReceiverUpdateDto.cs

@@ -3,5 +3,26 @@ using Microsoft.AspNetCore.Mvc;
 
 namespace EnvelopeGenerator.Application.DTOs.Receiver;
 
+/// <summary>
+/// Data Transfer Object for updating a receiver's information.
+/// </summary>
 [ApiExplorerSettings(IgnoreApi = true)]
-public record ReceiverUpdateDto(int Id, string? TotpSecretkey = null, DateTime? TfaRegDeadline = null) : IUnique<int>;
+public class ReceiverUpdateDto : IUnique<int>
+{
+    /// <summary>
+    /// Gets or sets the unique identifier of the receiver.
+    /// </summary>
+    public int Id { get; set; }
+
+    /// <summary>
+    /// Gets or sets the TOTP (Time-based One-Time Password) secret key.
+    /// Optional.
+    /// </summary>
+    public string? TotpSecretkey { get; set; }
+
+    /// <summary>
+    /// Gets or sets the deadline for two-factor authentication registration.
+    /// Optional.
+    /// </summary>
+    public DateTime? TfaRegDeadline { get; set; }
+}

EnvelopeGenerator.Application/DTOs/UserReceiverDto.cs

@@ -1,15 +1,46 @@
 using DigitalData.Core.Abstractions;
 using Microsoft.AspNetCore.Mvc;
 
-namespace EnvelopeGenerator.Application.DTOs
+namespace EnvelopeGenerator.Application.DTOs;
+
+/// <summary>
+/// Data Transfer Object representing a user receiver with associated details.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class UserReceiverDto : IUnique<int>
 {
-    [ApiExplorerSettings(IgnoreApi = true)]
+    /// <summary>
-    public record UserReceiverDto(
+    /// Gets or sets the unique identifier of the user receiver.
-        int Id,
+    /// </summary>
-        int UserId,
+    public int Id { get; set; }
-        int ReceiverId,
+
-        string Name,
+    /// <summary>
-        string CompanyName,
+    /// Gets or sets the identifier of the user associated with the receiver.
-        string JobTitle,
+    /// </summary>
-        DateTime AddedWhen) : IUnique<int>;
+    public int UserId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the identifier of the receiver.
+    /// </summary>
+    public int ReceiverId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the name of the receiver.
+    /// </summary>
+    public string Name { get; set; }
+
+    /// <summary>
+    /// Gets or sets the company name of the receiver.
+    /// </summary>
+    public string CompanyName { get; set; }
+
+    /// <summary>
+    /// Gets or sets the job title of the receiver.
+    /// </summary>
+    public string JobTitle { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when the user receiver was added.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
 }

EnvelopeGenerator.Application/Services/EnvelopeHistoryService.cs

@@ -76,7 +76,14 @@ public class EnvelopeHistoryService : CRUDService<IEnvelopeHistoryRepository, En
 		}
 
 		public async Task<DataResult<long>> RecordAsync(int envelopeId, string userReference, EnvelopeStatus status, string? comment = null) => 
-        await CreateAsync(new (EnvelopeId: envelopeId, UserReference: userReference, Status: (int)status, ActionDate: DateTime.Now, Comment: comment))
+        await CreateAsync(new ()
+        {
+            EnvelopeId = envelopeId,
+            UserReference = userReference,
+            Status = (int) status,
+            ActionDate = DateTime.Now,
+            Comment = comment
+        })
             .ThenAsync(
                 Success: id => Result.Success(id),
                 Fail: (mssg, ntc) => Result.Fail<long>().Message(mssg).Notice(ntc)

EnvelopeGenerator.Domain/Entities/Config.cs

@@ -1,28 +1,27 @@
-using DigitalData.Core.Abstractions;
+using System.ComponentModel.DataAnnotations;
-using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 using System.Text.Json.Serialization;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_CONFIG", Schema = "dbo")]
-    public class Config : IUnique<int>
+    public class Config
     {
         [Column("DOCUMENT_PATH", TypeName = "nvarchar(256)")]
-        public string? DocumentPath { get; init; }
+        public string DocumentPath { get; set; }
 
         [Column("SENDING_PROFILE", TypeName = "int")]
         [Required]
-        public required int SendingProfile { get; init; }
+        public int SendingProfile { get; set; }
 
         [Column("SIGNATURE_HOST", TypeName = "nvarchar(128)")]
-        public string? SignatureHost { get; init; }
+        public string SignatureHost { get; set; }
 
         [Column("EXTERNAL_PROGRAM_NAME", TypeName = "nvarchar(30)")]
-        public string? ExternalProgramName { get; init; }
+        public string ExternalProgramName { get; set; }
 
         [Column("EXPORT_PATH", TypeName = "nvarchar(256)")]
-        public string? ExportPath { get; init; }
+        public string ExportPath { get; set; }
 
         [Obsolete("Configuration does not have an ID; it represents a single table in the database.")]
         [NotMapped]

EnvelopeGenerator.Domain/Entities/DocumentReceiverElement.cs

@@ -1,12 +1,11 @@
-using DigitalData.Core.Abstractions;
+using System.ComponentModel;
-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 : IUnique<int>
+    public class DocumentReceiverElement
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
@@ -57,7 +56,7 @@ namespace EnvelopeGenerator.Domain.Entities
         public bool Required { get; set; }
 
         [Column("TOOLTIP")]
-        public string? Tooltip { get; set; }
+        public string Tooltip { get; set; }
 
         [Required]
         [Column("READ_ONLY")]
@@ -75,13 +74,13 @@ namespace EnvelopeGenerator.Domain.Entities
         public DateTime AddedWhen { get; set; }
 
         [Column("CHANGED_WHEN", TypeName = "datetime")]
-        public DateTime? ChangedWhen { get; set; }
+        public DateTime ChangedWhen { get; set; }
 
         [ForeignKey("DocumentId")]
-        public virtual EnvelopeDocument? Document { get; set; }
+        public virtual EnvelopeDocument Document { get; set; }
 
         [ForeignKey("ReceiverId")]
-        public virtual Receiver? Receiver { get; set; }
+        public virtual Receiver Receiver { get; set; }
 
         [NotMapped]
         public double Top => Math.Round(Y, 5);

EnvelopeGenerator.Domain/Entities/DocumentStatus.cs

@@ -1,11 +1,10 @@
-using DigitalData.Core.Abstractions;
+using System.ComponentModel.DataAnnotations;
-using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_DOCUMENT_STATUS", Schema = "dbo")]
-    public class DocumentStatus : IUnique<int>
+    public class DocumentStatus
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
@@ -25,22 +24,22 @@ namespace EnvelopeGenerator.Domain.Entities
         public int Status { get; set; }
 
         [Column("STATUS_CHANGED_WHEN", TypeName = "datetime")]
-        public DateTime? StatusChangedWhen { get; set; }
+        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")]
         public DateTime AddedWhen { get; set; }
 
         [Column("CHANGED_WHEN", TypeName = "datetime")]
-        public DateTime? ChangedWhen { get; set; }
+        public DateTime ChangedWhen { get; set; }
 
         [ForeignKey("EnvelopeId")]
-        public virtual Envelope? Envelope { get; set; }
+        public virtual Envelope Envelope { get; set; }
 
         [ForeignKey("ReceiverId")]
-        public virtual Receiver? Receiver { get; set; }
+        public virtual Receiver Receiver { get; set; }
     }
 }

EnvelopeGenerator.Domain/Entities/EmailTemplate.cs

@@ -1,12 +1,11 @@
-using DigitalData.Core.Abstractions;
+using System.ComponentModel;
-using System.ComponentModel;
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_EMAIL_TEMPLATE", Schema = "dbo")]
-    public class EmailTemplate : IUnique<int>
+    public class EmailTemplate
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
@@ -14,13 +13,13 @@ 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; }
 
         [Required]
         [Column("ADDED_WHEN", TypeName = "datetime")]
@@ -28,6 +27,6 @@ namespace EnvelopeGenerator.Domain.Entities
         public DateTime AddedWhen { get; set; }
 
         [Column("CHANGED_WHEN", TypeName = "datetime")]
-        public DateTime? ChangedWhen { get; set; }
+        public DateTime ChangedWhen { get; set; }
     }
 }

EnvelopeGenerator.Domain/Entities/Envelope.cs

@@ -1,12 +1,11 @@
-using DigitalData.Core.Abstractions;
+using EnvelopeGenerator.Common;
-using EnvelopeGenerator.Common;
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_ENVELOPE", Schema = "dbo")]
-    public class Envelope : IUnique<int>
+    public class Envelope
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
@@ -22,90 +21,90 @@ namespace EnvelopeGenerator.Domain.Entities
         public int Status { get; set; }
 
         [NotMapped]
-        public string StatusName  => ((Constants.EnvelopeStatus)Status).ToString();
+        public string StatusName => ((Constants.EnvelopeStatus)Status).ToString();
 
         [Required]
         [Column("ENVELOPE_UUID", TypeName = "nvarchar(36)")]
-        public required string Uuid { get; init; }
+        public string Uuid { get; set; }
 
         [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; }
+        public DateTime ExpiresWhen { get; set; }
 
         [Column("EXPIRES_WARNING_WHEN", TypeName = "datetime")]
-        public DateTime? ExpiresWarningWhen { get; set; }
+        public DateTime ExpiresWarningWhen { get; set; }
 
         [Required]
         [Column("ADDED_WHEN", TypeName = "datetime")]
         public DateTime AddedWhen { get; set; }
 
         [Column("CHANGED_WHEN", TypeName = "datetime")]
-        public DateTime? ChangedWhen { get; set; }
+        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; }
+        public int ContractType { get; set; }
 
         [Column("LANGUAGE", TypeName = "nvarchar(5)")]
-        public string? Language { get; set; }
+        public string Language { get; set; }
 
         [Column("SEND_REMINDER_EMAILS")]
-        public bool? SendReminderEmails { get; set; }
+        public bool SendReminderEmails { get; set; }
 
         [Column("FIRST_REMINDER_DAYS")]
-        public int? FirstReminderDays { get; set; }
+        public int FirstReminderDays { get; set; }
 
         [Column("REMINDER_INTERVAL_DAYS")]
-        public int? ReminderIntervalDays { get; set; }
+        public int ReminderIntervalDays { get; set; }
 
         [Column("ENVELOPE_TYPE")]
-        public int? EnvelopeTypeId { get; set; }
+        public int EnvelopeTypeId { get; set; }
 
         [Column("CERTIFICATION_TYPE")]
-        public int? CertificationType { get; set; }
+        public int CertificationType { get; set; }
 
         [Column("USE_ACCESS_CODE")]
-        public bool? UseAccessCode { get; set; }
+        public bool UseAccessCode { get; set; }
 
         [Column("FINAL_EMAIL_TO_CREATOR")]
-        public int? FinalEmailToCreator { get; set; }
+        public int FinalEmailToCreator { get; set; }
 
         [Column("FINAL_EMAIL_TO_RECEIVERS")]
-        public int? FinalEmailToReceivers { get; set; }
+        public int FinalEmailToReceivers { get; set; }
 
         [Column("EXPIRES_WHEN_DAYS")]
-        public int? ExpiresWhenDays { get; set; }
+        public int ExpiresWhenDays { get; set; }
 
         [Column("EXPIRES_WARNING_WHEN_DAYS")]
-        public int? ExpiresWarningWhenDays { get; set; }
+        public int ExpiresWarningWhenDays { get; set; }
 
         [Column("TFA_ENABLED", TypeName = "bit")]
         public bool TFAEnabled { get; set; }
 
         [Column("DOC_RESULT", TypeName = "varbinary(max)")]
-        public byte[]? DocResult { get; init; }
+        public byte[] DocResult { get; set; }
 
         /// <summary>
         /// The sender of envelope
         /// </summary>
         [ForeignKey("UserId")]
-        public DigitalData.UserManager.Domain.Entities.User? User { get; set; }
+        public User User { get; set; }
 
         [ForeignKey("EnvelopeTypeId")]
-        public EnvelopeType? EnvelopeType { get; set; }
+        public EnvelopeType EnvelopeType { get; set; }
 
         [NotMapped]
-        public string? EnvelopeTypeTitle => EnvelopeType?.Title;
+        public string EnvelopeTypeTitle => EnvelopeType.Title;
 
         [NotMapped]
-        public bool IsAlreadySent => Status > (int) Constants.EnvelopeStatus.EnvelopeSaved;
+        public bool IsAlreadySent => Status > (int)Constants.EnvelopeStatus.EnvelopeSaved;
 
-        public IEnumerable<EnvelopeDocument>? Documents { get; set; }
+        public IEnumerable<EnvelopeDocument> Documents { get; set; }
 
-        public IEnumerable<EnvelopeHistory>? History { get; set; }
+        public IEnumerable<EnvelopeHistory> History { get; set; }
     }
 }

EnvelopeGenerator.Domain/Entities/EnvelopeCertificate.cs

@@ -1,11 +1,10 @@
-using DigitalData.Core.Abstractions;
+using System.ComponentModel.DataAnnotations;
-using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_ENVELOPE_CERTIFICATE", Schema = "dbo")]
-    public class EnvelopeCertificate : IUnique<int>
+    public class EnvelopeCertificate
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
@@ -18,11 +17,11 @@ namespace EnvelopeGenerator.Domain.Entities
 
         [Required]
         [Column("ENVELOPE_UUID", TypeName = "nvarchar(36)")]
-        public required string EnvelopeUuid { get; set; }
+        public string EnvelopeUuid { get; set; }
 
         [Required]
         [Column("ENVELOPE_SUBJECT", TypeName = "nvarchar(512)")]
-        public required string EnvelopeSubject { get; set; }
+        public string EnvelopeSubject { get; set; }
 
         [Required]
         [Column("CREATOR_ID")]
@@ -30,11 +29,11 @@ namespace EnvelopeGenerator.Domain.Entities
 
         [Required]
         [Column("CREATOR_NAME", TypeName = "nvarchar(128)")]
-        public required string CreatorName { get; set; }
+        public string CreatorName { get; set; }
 
         [Required]
         [Column("CREATOR_EMAIL", TypeName = "nvarchar(128)")]
-        public required string CreatorEmail { get; set; }
+        public string CreatorEmail { get; set; }
 
         [Required]
         [Column("ENVELOPE_STATUS")]

EnvelopeGenerator.Domain/Entities/EnvelopeDocument.cs

@@ -1,27 +1,27 @@
-using DigitalData.Core.Abstractions;
+using System.ComponentModel.DataAnnotations;
-using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
-namespace EnvelopeGenerator.Domain.Entities;
+namespace EnvelopeGenerator.Domain.Entities
-
-[Table("TBSIG_ENVELOPE_DOCUMENT", Schema = "dbo")]
-public class EnvelopeDocument : IUnique<int>
 {
-    [Key]
+    [Table("TBSIG_ENVELOPE_DOCUMENT", Schema = "dbo")]
-    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
+    public class EnvelopeDocument
-    [Column("GUID")]
+    {
-    public int Id { get; set; }
+        [Key]
+        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
+        [Column("GUID")]
+        public int Id { get; set; }
 
-    [Required]
+        [Required]
-    [Column("ENVELOPE_ID")]
+        [Column("ENVELOPE_ID")]
-    public int EnvelopeId { get; set; }
+        public int EnvelopeId { get; set; }
 
-    [Required]
+        [Required]
-    [Column("ADDED_WHEN", TypeName = "datetime")]
+        [Column("ADDED_WHEN", TypeName = "datetime")]
-    public required DateTime AddedWhen { get; set; }
+        public DateTime AddedWhen { get; set; }
 
-    [Column("BYTE_DATA", TypeName = "varbinary(max)")]
+        [Column("BYTE_DATA", TypeName = "varbinary(max)")]
-    public byte[]? ByteData { get; init; }
+        public byte[] ByteData { get; set; }
 
-    public IEnumerable<DocumentReceiverElement>? Elements { get; set; }
+        public IEnumerable<DocumentReceiverElement> Elements { get; set; }
+    }
 }

EnvelopeGenerator.Domain/Entities/EnvelopeHistory.cs

@@ -1,12 +1,10 @@
-using DigitalData.Core.Abstractions;
+using System.ComponentModel.DataAnnotations;
-using DigitalData.UserManager.Domain.Entities;
-using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_ENVELOPE_HISTORY", Schema = "dbo")]
-    public class EnvelopeHistory : IUnique<long>
+    public class EnvelopeHistory
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
@@ -19,7 +17,7 @@ namespace EnvelopeGenerator.Domain.Entities
 
         [Required]
         [Column("USER_REFERENCE", TypeName = "nvarchar(128)")]
-        public required string UserReference { get; init; }
+        public string UserReference { get; set; }
 
         [Required]
         [Column("STATUS")]
@@ -31,15 +29,15 @@ namespace EnvelopeGenerator.Domain.Entities
         public DateTime AddedWhen { get; set; }
 
         [Column("ACTION_DATE", TypeName = "datetime")]
-        public DateTime? ActionDate { get; set; }
+        public DateTime ActionDate { get; set; }
 
         [Column("COMMENT", TypeName = "nvarchar(max)")]
-        public string? Comment { get; set; }
+        public string Comment { get; set; }
 
         [ForeignKey("UserReference")]
-        public virtual User? Sender { get; set; }
+        public virtual User Sender { get; set; }
 
         [ForeignKey("UserReference")]
-        public virtual Receiver? Receiver { get; set; }
+        public virtual Receiver Receiver { get; set; }
     }
 }

EnvelopeGenerator.Domain/Entities/EnvelopeReceiver.cs

@@ -6,9 +6,9 @@ namespace EnvelopeGenerator.Domain.Entities
     public class EnvelopeReceiver : EnvelopeReceiverBase
     {
         [ForeignKey("EnvelopeId")]
-        public Envelope? Envelope { get; set; }
+        public Envelope Envelope { get; set; }
 
         [ForeignKey("ReceiverId")]
-        public Receiver? Receiver { get; set; }
+        public Receiver Receiver { get; set; }
     }
 }

EnvelopeGenerator.Domain/Entities/EnvelopeReceiverBase.cs

@@ -1,11 +1,10 @@
-using DigitalData.Core.Abstractions;
+using System.ComponentModel.DataAnnotations;
-using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_ENVELOPE_RECEIVER", Schema = "dbo")]
-    public class EnvelopeReceiverBase : IUnique<(int Envelope, int Receiver)>
+    public class EnvelopeReceiverBase
     {
         [Key]
         [Column("ENVELOPE_ID")]
@@ -20,31 +19,31 @@ namespace EnvelopeGenerator.Domain.Entities
         public int Sequence { get; set; }
 
         [Column("NAME", TypeName = "nvarchar(128)")]
-        public string? Name { get; set; }
+        public string Name { get; set; }
 
         [Column("JOB_TITLE", TypeName = "nvarchar(128)")]
-        public string? JobTitle { get; set; }
+        public string JobTitle { get; set; }
 
         [Column("COMPANY_NAME", TypeName = "nvarchar(128)")]
-        public string? CompanyName { get; set; }
+        public string CompanyName { get; set; }
 
         [Column("PRIVATE_MESSAGE", TypeName = "nvarchar(max)")]
-        public string? PrivateMessage { get; set; }
+        public string PrivateMessage { get; set; }
 
         [Column("ACCESS_CODE", TypeName = "nvarchar(64)")]
-        public string? AccessCode { get; set; }
+        public string AccessCode { get; set; }
 
         [Required]
         [Column("ADDED_WHEN", TypeName = "datetime")]
         public DateTime AddedWhen { get; set; }
 
         [Column("CHANGED_WHEN", TypeName = "datetime")]
-        public DateTime? ChangedWhen { get; set; }
+        public DateTime ChangedWhen { get; set; }
 
         [Column("PHONE_NUMBER")]
         [StringLength(20)]
         [RegularExpression(@"^\+[0-9]+$", ErrorMessage = "Phone number must start with '+' followed by digits.")]
-        public string? PhoneNumber { get; set; }
+        public string PhoneNumber { get; set; }
         
         [NotMapped]
         public (int Envelope, int Receiver) Id => (Envelope: EnvelopeId, Receiver: ReceiverId);

EnvelopeGenerator.Domain/Entities/EnvelopeReceiverReadOnly.cs

@@ -1,52 +1,50 @@
 using System.ComponentModel.DataAnnotations.Schema;
 using System.ComponentModel.DataAnnotations;
-using DigitalData.Core.Abstractions;
-using DigitalData.EmailProfilerDispatcher.Abstraction.Attributes;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_ENVELOPE_RECEIVER_READ_ONLY")]
-    public class EnvelopeReceiverReadOnly : IUnique<long>
+    public class EnvelopeReceiverReadOnly
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
         [Column("GUID")]
-        public long Id { get; init; }
+        public long Id { get; set; }
 
         [Column("ENVELOPE_ID")]
         [Required]
-        public long EnvelopeId { get; init; }
+        public long EnvelopeId { get; set; }
 
         //TODO: remove NotMapped attribute when EnvelopeId data type is standardized
         [NotMapped]
-        public Envelope? Envelope { get; set; }
+        public Envelope Envelope { get; set; }
 
         [Column("RECEIVER_MAIL")]
         [Required]
         [StringLength(250)]
         [TemplatePlaceholder("NAME_RECEIVER")]
-        public required string ReceiverMail { get; init; }
+        public string ReceiverMail { get; set; }
 
         [Column("DATE_VALID")]
         [Required]
-        public DateTime DateValid { get; init; }
+        public DateTime DateValid { get; set; }
 
         [Column("ADDED_WHO")]
         [Required]
         [StringLength(100)]
-        public required string AddedWho { get; init; }
+        public string AddedWho { get; set; }
 
-        public Receiver? Receiver { get; init; }
+        public Receiver Receiver { get; set; }
 
         [Column("ADDED_WHEN")]
         [Required]
-        public DateTime AddedWhen { get; init; }
+        public DateTime AddedWhen { get; set; }
 
         [Column("CHANGED_WHO")]
         [StringLength(100)]
-        public string? ChangedWho { get; init; }
+        public string ChangedWho { get; set; }
 
         [Column("CHANGED_WHEN")]
-        public DateTime? ChangedWhen { get; init; }
+        public DateTime ChangedWhen { get; set; }
     }
 }

EnvelopeGenerator.Domain/Entities/EnvelopeType.cs

@@ -1,11 +1,10 @@
-using DigitalData.Core.Abstractions;
+using System.ComponentModel.DataAnnotations;
-using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_ENVELOPE_TYPE", Schema = "dbo")]
-    public class EnvelopeType : IUnique<int>
+    public class EnvelopeType
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
@@ -14,46 +13,46 @@ namespace EnvelopeGenerator.Domain.Entities
 
         [Required]
         [Column("TITLE", TypeName = "nvarchar(128)")]
-        public required string Title { get; set; }
+        public 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; }
+        public int ExpiresDays { get; set; }
 
         [Column("CERTIFICATION_TYPE")]
-        public int? CertificationType { get; set; }
+        public int CertificationType { get; set; }
 
         [Column("USE_ACCESS_CODE")]
-        public bool? UseAccessCode { get; set; }
+        public bool UseAccessCode { get; set; }
 
         [Column("FINAL_EMAIL_TO_CREATOR")]
-        public int? FinalEmailToCreator { get; set; }
+        public int FinalEmailToCreator { get; set; }
 
         [Column("FINAL_EMAIL_TO_RECEIVERS")]
-        public int? FinalEmailToReceivers { get; set; }
+        public int FinalEmailToReceivers { get; set; }
 
         [Required]
         [Column("ADDED_WHEN", TypeName = "datetime")]
         public DateTime AddedWhen { get; set; }
 
         [Column("CHANGED_WHEN", TypeName = "datetime")]
-        public DateTime? ChangedWhen { get; set; }
+        public DateTime ChangedWhen { get; set; }
 
         [Column("EXPIRES_WARNING_DAYS")]
-        public int? ExpiresWarningDays { get; set; }
+        public int ExpiresWarningDays { get; set; }
 
         [Column("SEND_REMINDER_EMAILS")]
-        public bool? SendReminderEmails { get; set; }
+        public bool SendReminderEmails { get; set; }
 
         [Column("FIRST_REMINDER_DAYS")]
-        public int? FirstReminderDays { get; set; }
+        public int FirstReminderDays { get; set; }
 
         [Column("REMINDER_INTERVAL_DAYS")]
-        public int? ReminderIntervalDays { get; set; }
+        public int ReminderIntervalDays { get; set; }
 
         [Column("CONTRACT_TYPE")]
-        public int? ContractType { get; set; }
+        public int ContractType { get; set; }
     }
 }

EnvelopeGenerator.Domain/Entities/Receiver.cs

@@ -1,34 +1,34 @@
-using DigitalData.Core.Abstractions;
+using System.ComponentModel.DataAnnotations;
-using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
-namespace EnvelopeGenerator.Domain.Entities;
+namespace EnvelopeGenerator.Domain.Entities
-
-[Table("TBSIG_RECEIVER", Schema = "dbo")]
-public class Receiver : IUnique<int>
 {
-    [Key]
+    [Table("TBSIG_RECEIVER", Schema = "dbo")]
-    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
+    public class Receiver
-    [Column("GUID")]
+    {
-    public int Id { get; set; }
+        [Key]
-    
+        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
-    [Required, EmailAddress]
+        [Column("GUID")]
-    [Column("EMAIL_ADDRESS", TypeName = "nvarchar(128)")]
+        public int Id { get; set; }
-    public required string EmailAddress { get; set; }
 
-    [Required]
+        [Required, EmailAddress]
-    [Column("SIGNATURE", TypeName = "nvarchar(64)")]
+        [Column("EMAIL_ADDRESS", TypeName = "nvarchar(128)")]
-    public required string Signature { get; set; }
+        public string EmailAddress { get; set; }
 
-    [Required]
+        [Required]
-    [Column("ADDED_WHEN", TypeName = "datetime")]
+        [Column("SIGNATURE", TypeName = "nvarchar(64)")]
-    public DateTime AddedWhen { get; set; }
+        public string Signature { get; set; }
 
-    [Column("TOTP_SECRET_KEY", TypeName = "nvarchar(MAX)")]
+        [Required]
-    public string? TotpSecretkey { get; set; }
+        [Column("ADDED_WHEN", TypeName = "datetime")]
+        public DateTime AddedWhen { get; set; }
 
-    [Column("TFA_REG_DEADLINE", TypeName = "datetime")]
+        [Column("TOTP_SECRET_KEY", TypeName = "nvarchar(MAX)")]
-    public DateTime? TfaRegDeadline { get; set; }
+        public string TotpSecretkey { get; set; }
 
-    public IEnumerable<EnvelopeReceiver>? EnvelopeReceivers { get; init; }
+        [Column("TFA_REG_DEADLINE", TypeName = "datetime")]
+        public DateTime TfaRegDeadline { get; set; }
+
+        public IEnumerable<EnvelopeReceiver> EnvelopeReceivers { get; set; }
+    }
 }

EnvelopeGenerator.Domain/Entities/User.cs

@@ -0,0 +1,96 @@
+using System.ComponentModel.DataAnnotations.Schema;
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel;
+
+namespace EnvelopeGenerator.Domain.Entities
+{
+    [Table("TBDD_USER", Schema = "dbo")]
+    public class User
+    {
+        [Column("GUID")]
+        [Key]
+        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
+        public int Id { get; set; }
+
+        [StringLength(50)]
+        [Column("ADDED_WHO")]
+        public string AddedWho { get; set; }
+
+        [StringLength(50)]
+        [Column("CHANGED_WHO")]
+        public string ChangedWho { get; set; }
+
+        //TODO: assign it to default value in create dto, not here!
+        [Column("ADDED_WHEN", TypeName = "datetime")]
+        [DefaultValue("GETDATE()")]
+        public DateTime AddedWhen { get; set; } = DateTime.Now;
+
+        [Column("CHANGED_WHEN", TypeName = "datetime")]
+        public DateTime ChangedWhen { get; set; }
+
+        [Column("PRENAME")]
+        [StringLength(50)]
+        public string Prename { get; set; }
+
+        [Column("NAME")]
+        [StringLength(50)]
+        public string Name { get; set; }
+
+        [Required]
+        [Column("USERNAME")]
+        [StringLength(50)]
+        public string Username { get; set; }
+
+        [Column("SHORTNAME")]
+        [StringLength(30)]
+        public string Shortname { get; set; }
+
+        [Column("EMAIL")]
+        [StringLength(100)]
+        public string Email { get; set; }
+
+        [Required]
+        [Column("LANGUAGE")]
+        [StringLength(5)]
+        [DefaultValue("de-DE")]
+        public string Language { get; set; }
+
+        [Column("COMMENT")]
+        [StringLength(500)]
+        public string Comment { 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("ACTIVE")]
+        public bool Active { get; set; }
+
+        [Required]
+        [Column("GENERAL_VIEWER")]
+        [StringLength(30)]
+        [DefaultValue("NONE")]
+        public string GeneralViewer { get; set; }
+
+        [Required]
+        [Column("WAN_ENVIRONMENT")]
+        public bool WanEnvironment { get; set; }
+
+        [Required]
+        [Column("USERID_FK_INT_ECM")]
+        public int UseridFkIntEcm { get; set; }
+
+        [Column("DELETED_WHEN")]
+        public DateTime DeletedWhen { get; set; }
+
+        [Column("DELETED_WHO")]
+        [StringLength(50)]
+        public string DeletedWho { get; set; }
+    }
+}

EnvelopeGenerator.Domain/Entities/UserReceiver.cs

@@ -1,11 +1,10 @@
-using DigitalData.Core.Abstractions;
+using System.ComponentModel.DataAnnotations;
-using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_USER_RECEIVER", Schema = "dbo")]
-    public class UserReceiver : IUnique<int>
+    public class UserReceiver
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
@@ -22,16 +21,16 @@ namespace EnvelopeGenerator.Domain.Entities
 
         [Required]
         [Column("NAME", TypeName = "nvarchar(128)")]
-        public required string Name { get; set; }
+        public 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 required DateTime AddedWhen { get; init; }
+        public DateTime AddedWhen { get; set; }
     }
 }

EnvelopeGenerator.Domain/EnvelopeGenerator.Domain.csproj

@@ -1,15 +1,12 @@
 <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>
   </PropertyGroup>
 
-  <ItemGroup>
+  <ItemGroup Condition="'$(TargetFramework)' == 'net462'">
-    <PackageReference Include="DigitalData.Core.Abstractions" Version="3.6.0" />
+	  <PackageReference Include="System.ComponentModel.Annotations" Version="4.7.0" />
-    <PackageReference Include="DigitalData.EmailProfilerDispatcher.Abstraction" Version="3.0.0" />
-    <PackageReference Include="UserManager.Domain" Version="3.0.2" />
   </ItemGroup>
 
   <ItemGroup>

EnvelopeGenerator.Infrastructure/DependencyExtensions.cs

@@ -33,7 +33,7 @@ public static class DIExtensions
     /// will be created per HTTP request (or per scope) within the dependency injection container.
     /// </remarks>
     public static IServiceCollection AddEnvelopeGeneratorInfrastructureServices(this IServiceCollection services,
-        Action<DbContextOptionsBuilder>? dbContextOptions = null,
+        Action<IServiceProvider, DbContextOptionsBuilder>? dbContextOptions = null,
         IConfiguration? sqlExecutorConfiguration = null,
         Action<SQLExecutorParams>? sqlExecutorConfigureOptions = null)
     {

EnvelopeGenerator.Web/Program.cs

@@ -98,7 +98,14 @@ try
     });
 
     // Add envelope generator services
-    builder.Services.AddEnvelopeGeneratorInfrastructureServices(options => options.UseSqlServer(connStr));
+    builder.Services.AddEnvelopeGeneratorInfrastructureServices((provider, options) =>
+    {
+        var logger = provider.GetRequiredService<ILogger<EGDbContext>>();
+        options.UseSqlServer(connStr)
+               .LogTo(log => logger.LogInformation("{log}", log), Microsoft.Extensions.Logging.LogLevel.Trace)
+               .EnableSensitiveDataLogging()
+               .EnableDetailedErrors();
+    });
 
     builder.Services.AddEnvelopeGeneratorServices(config);