diff --git a/src/Altinn.Correspondence.API/Mappers/LegacyCorrespondenceOverviewMapper.cs b/src/Altinn.Correspondence.API/Mappers/LegacyCorrespondenceOverviewMapper.cs
index 85f734ef..456c3b63 100644
--- a/src/Altinn.Correspondence.API/Mappers/LegacyCorrespondenceOverviewMapper.cs
+++ b/src/Altinn.Correspondence.API/Mappers/LegacyCorrespondenceOverviewMapper.cs
@@ -20,7 +20,12 @@ internal static LegacyCorrespondenceOverviewExt MapToExternal(LegacyGetCorrespon
             Created = correspondenceOverview.Created,
             Notifications = correspondenceOverview.Notifications,
             Recipient = correspondenceOverview.Recipient,
-            Content = CorrespondenceContentMapper.MapToExternal(correspondenceOverview.Content),
+            Content = null,
+            Attachments = CorrespondenceAttachmentMapper.MapListToExternal(correspondenceOverview.Attachments),
+            Language = correspondenceOverview.Language,
+            MessageTitle = correspondenceOverview.MessageTitle,
+            MessageSummary = correspondenceOverview.MessageSummary,
+            MessageBody = correspondenceOverview.MessageBody,
             ReplyOptions = CorrespondenceReplyOptionsMapper.MapListToExternal(correspondenceOverview.ReplyOptions),
             ExternalReferences = ExternalReferenceMapper.MapListToExternal(correspondenceOverview.ExternalReferences),
             ResourceId = correspondenceOverview.ResourceId.ToString(),
@@ -36,6 +41,7 @@ internal static LegacyCorrespondenceOverviewExt MapToExternal(LegacyGetCorrespon
             Archived = correspondenceOverview.Archived,
             MinimumAuthenticationLevel = correspondenceOverview.MinimumAuthenticationLevel,
             AuthorizedForSign = correspondenceOverview.AuthorizedForSign,
+            InstanceOwnerPartyId = correspondenceOverview.InstanceOwnerPartyId
         };
         return Correspondence;
     }
diff --git a/src/Altinn.Correspondence.API/Models/LegacyCorrespondenceOverviewExt.cs b/src/Altinn.Correspondence.API/Models/LegacyCorrespondenceOverviewExt.cs
index 853dadd6..90e4afd6 100644
--- a/src/Altinn.Correspondence.API/Models/LegacyCorrespondenceOverviewExt.cs
+++ b/src/Altinn.Correspondence.API/Models/LegacyCorrespondenceOverviewExt.cs
@@ -38,5 +38,45 @@ public class LegacyCorrespondenceOverviewExt : CorrespondenceOverviewExt
         /// </summary>
         [JsonPropertyName("archived")]
         public DateTimeOffset? Archived { get; set; }
+
+        /// <summary>
+        /// Gets or sets the language of the correspondence, specified according to ISO 639-1 
+        /// </summary>
+        [JsonPropertyName("language")]
+        [ISO6391]
+        public required string Language { get; set; }
+
+        /// <summary>
+        /// Gets or sets the correspondence message title. Subject.
+        /// </summary>
+        /// <remarks>
+        /// TODO: Length restriction?
+        /// </remarks>
+        [JsonPropertyName("messageTitle")]
+        public required string MessageTitle { get; set; }
+
+        /// <summary>
+        /// Gets or sets a summary text of the correspondence.
+        /// </summary>
+        /// <remarks>
+        /// TODO: Length restriction?
+        /// </remarks>
+        [JsonPropertyName("messageSummary")]
+        public required string MessageSummary { get; set; }
+
+        /// <summary>
+        /// Gets or sets the main body of the correspondence.
+        /// </summary>
+        [JsonPropertyName("messageBody")]
+        public required string MessageBody { get; set; }
+
+        [JsonPropertyName("attachments")]
+        public required new List<CorrespondenceAttachmentExt> Attachments { get; set; }
+
+        /// <summary>
+        /// Instance owner party id
+        /// </summary>
+        [JsonPropertyName("instanceOwnerPartyId")]
+        public int InstanceOwnerPartyId { get; set; }
     }
 }
\ No newline at end of file
diff --git a/src/Altinn.Correspondence.Application/GetCorespondences/LegacyGetCorrespondencesHandler.cs b/src/Altinn.Correspondence.Application/GetCorespondences/LegacyGetCorrespondencesHandler.cs
index 3878e242..8802a10e 100644
--- a/src/Altinn.Correspondence.Application/GetCorespondences/LegacyGetCorrespondencesHandler.cs
+++ b/src/Altinn.Correspondence.Application/GetCorespondences/LegacyGetCorrespondencesHandler.cs
@@ -6,6 +6,8 @@
 using Altinn.Correspondence.Repositories;
 using OneOf;
 
+using Microsoft.Extensions.Logging;
+
 namespace Altinn.Correspondence.Application.GetCorrespondences;
 
 public class LegacyGetCorrespondencesHandler : IHandler<LegacyGetCorrespondencesRequest, LegacyGetCorrespondencesResponse>
@@ -16,10 +18,11 @@ public class LegacyGetCorrespondencesHandler : IHandler<LegacyGetCorrespondences
     private readonly ICorrespondenceRepository _correspondenceRepository;
     private readonly IResourceRightsService _resourceRightsService;
     private readonly UserClaimsHelper _userClaimsHelper;
+    private readonly ILogger<LegacyGetCorrespondencesHandler> _logger;
     private record ResourceOwner(string OrgNumber, Party? Party);
 
 
-    public LegacyGetCorrespondencesHandler(IAltinnAuthorizationService altinnAuthorizationService, IAltinnAccessManagementService altinnAccessManagement, ICorrespondenceRepository correspondenceRepository, UserClaimsHelper userClaimsHelper, IAltinnRegisterService altinnRegisterService, IResourceRightsService resourceRightsService)
+    public LegacyGetCorrespondencesHandler(IAltinnAuthorizationService altinnAuthorizationService, IAltinnAccessManagementService altinnAccessManagement, ICorrespondenceRepository correspondenceRepository, UserClaimsHelper userClaimsHelper, IAltinnRegisterService altinnRegisterService, IResourceRightsService resourceRightsService, ILogger<LegacyGetCorrespondencesHandler> logger)
     {
         _altinnAuthorizationService = altinnAuthorizationService;
         _altinnAccessManagementService = altinnAccessManagement;
@@ -27,6 +30,7 @@ public LegacyGetCorrespondencesHandler(IAltinnAuthorizationService altinnAuthori
         _userClaimsHelper = userClaimsHelper;
         _altinnRegisterService = altinnRegisterService;
         _resourceRightsService = resourceRightsService;
+        _logger = logger;
     }
 
     public async Task<OneOf<LegacyGetCorrespondencesResponse, Error>> Process(LegacyGetCorrespondencesRequest request, CancellationToken cancellationToken)
@@ -79,6 +83,7 @@ public async Task<OneOf<LegacyGetCorrespondencesResponse, Error>> Process(Legacy
         List<LegacyCorrespondenceItem> correspondenceItems = new List<LegacyCorrespondenceItem>();
 
         var resourceOwners = new List<ResourceOwner>();
+
         foreach (var orgNr in correspondences.Item1.Select(c => c.Sender).Distinct().ToList())
         {
             try
@@ -91,16 +96,31 @@ public async Task<OneOf<LegacyGetCorrespondencesResponse, Error>> Process(Legacy
                 resourceOwners.Add(new ResourceOwner(orgNr, null));
             }
         }
+        var recipientDetails = new List<ResourceOwner>();
+        foreach (var orgNr in correspondences.Item1.Select(c => c.Recipient).Distinct().ToList())
+        {
+            try
+            {
+                var recipientParty = await _altinnRegisterService.LookUpPartyById(orgNr, cancellationToken);
+                recipientDetails.Add(new ResourceOwner(orgNr, recipientParty));
+            }
+            catch (Exception e)
+            {
+                _logger.LogError(e, "Failed to lookup recipient party for orgNr: {OrgNr}", orgNr);
+                recipientDetails.Add(new ResourceOwner(orgNr, null));
+            }
+        }
         foreach (var correspondence in correspondences.Item1)
         {
             var purgedStatus = correspondence.GetPurgedStatus();
             var owner = resourceOwners.SingleOrDefault(r => r.OrgNumber == correspondence.Sender)?.Party;
+            var recipient = recipientDetails.SingleOrDefault(r => r.OrgNumber == correspondence.Recipient)?.Party;
             correspondenceItems.Add(
                 new LegacyCorrespondenceItem()
                 {
                     Altinn2CorrespondenceId = correspondence.Altinn2CorrespondenceId,
                     ServiceOwnerName = owner.Name,
-                    InstanceOwnerPartyId = owner.PartyId,
+                    InstanceOwnerPartyId = recipient?.PartyId ?? 0,
                     MessageTitle = correspondence.Content.MessageTitle,
                     Status = correspondence.GetLatestStatusWithoutPurged().Status,
                     CorrespondenceId = correspondence.Id,
@@ -108,8 +128,9 @@ public async Task<OneOf<LegacyGetCorrespondencesResponse, Error>> Process(Legacy
                     Published = correspondence.Published,
                     PurgedStatus = purgedStatus?.Status,
                     Purged = purgedStatus?.StatusChanged,
-                    DueDate = correspondence.DueDateTime,
+                    DueDateTime = correspondence.DueDateTime,
                     Archived = correspondence.Statuses?.FirstOrDefault(s => s.Status == CorrespondenceStatus.Archived)?.StatusChanged,
+                    Confirmed = correspondence.Statuses?.FirstOrDefault(s => s.Status == CorrespondenceStatus.Confirmed)?.StatusChanged,
                     MessageSender = correspondence.MessageSender
                 }
                 );
diff --git a/src/Altinn.Correspondence.Application/GetCorespondences/LegacyGetCorrespondencesResponse.cs b/src/Altinn.Correspondence.Application/GetCorespondences/LegacyGetCorrespondencesResponse.cs
index 6e72e734..f26afe5e 100644
--- a/src/Altinn.Correspondence.Application/GetCorespondences/LegacyGetCorrespondencesResponse.cs
+++ b/src/Altinn.Correspondence.Application/GetCorespondences/LegacyGetCorrespondencesResponse.cs
@@ -22,8 +22,9 @@ public class LegacyCorrespondenceItem
         public CorrespondenceStatus? PurgedStatus { get; set; }
         public DateTimeOffset? Purged { get; set; }
         public int InstanceOwnerPartyId { get; set; }
-        public DateTimeOffset? DueDate { get; set; }
+        public DateTimeOffset? DueDateTime { get; set; }
         public DateTimeOffset? Archived { get; set; }
         public string? MessageSender { get; set; }
+        public DateTimeOffset? Confirmed { get; set; }
     }
 }
diff --git a/src/Altinn.Correspondence.Application/GetCorrespondenceOverview/LegacyGetCorrespondenceOverviewHandler.cs b/src/Altinn.Correspondence.Application/GetCorrespondenceOverview/LegacyGetCorrespondenceOverviewHandler.cs
index f515af68..c49327e7 100644
--- a/src/Altinn.Correspondence.Application/GetCorrespondenceOverview/LegacyGetCorrespondenceOverviewHandler.cs
+++ b/src/Altinn.Correspondence.Application/GetCorrespondenceOverview/LegacyGetCorrespondenceOverviewHandler.cs
@@ -16,7 +16,6 @@ public class LegacyGetCorrespondenceOverviewHandler : IHandler<LegacyGetCorrespo
     private readonly IAltinnRegisterService _altinnRegisterService;
     private readonly ICorrespondenceRepository _correspondenceRepository;
     private readonly ICorrespondenceStatusRepository _correspondenceStatusRepository;
-    private readonly UserClaimsHelper _userClaimsHelper;
     private readonly ILogger<LegacyGetCorrespondenceOverviewHandler> _logger;
 
     public LegacyGetCorrespondenceOverviewHandler(IAltinnAccessManagementService altinnAccessManagementService, IAltinnAuthorizationService altinnAuthorizationService, IAltinnRegisterService altinnRegisterService, ICorrespondenceRepository CorrespondenceRepository, ICorrespondenceStatusRepository correspondenceStatusRepository, UserClaimsHelper userClaimsHelper, ILogger<LegacyGetCorrespondenceOverviewHandler> logger)
@@ -26,7 +25,6 @@ public LegacyGetCorrespondenceOverviewHandler(IAltinnAccessManagementService alt
         _altinnRegisterService = altinnRegisterService;
         _correspondenceRepository = CorrespondenceRepository;
         _correspondenceStatusRepository = correspondenceStatusRepository;
-        _userClaimsHelper = userClaimsHelper;
         _logger = logger;
     }
 
@@ -100,18 +98,26 @@ await _correspondenceStatusRepository.AddCorrespondenceStatus(new Correspondence
                 });
             }
         }
-
+        var resourceOwnerParty = await _altinnRegisterService.LookUpPartyById(correspondence.Sender, cancellationToken);
+        if (resourceOwnerParty == null)
+        {
+            return Errors.CouldNotFindOrgNo;
+        }
         var response = new LegacyGetCorrespondenceOverviewResponse
         {
             CorrespondenceId = correspondence.Id,
-            Content = correspondence.Content,
+            Attachments = correspondence.Content!.Attachments ?? new List<CorrespondenceAttachmentEntity>(),
+            Language = correspondence.Content!.Language,
+            MessageTitle = correspondence.Content!.MessageTitle,
+            MessageSummary = correspondence.Content!.MessageSummary,
+            MessageBody = correspondence.Content!.MessageBody,
             Status = latestStatus.Status,
             StatusText = latestStatus.StatusText,
             StatusChanged = latestStatus.StatusChanged,
             ResourceId = correspondence.ResourceId,
             Sender = correspondence.Sender,
             SendersReference = correspondence.SendersReference,
-            MessageSender = correspondence.MessageSender ?? string.Empty,
+            MessageSender = String.IsNullOrWhiteSpace(correspondence.MessageSender) ? resourceOwnerParty.Name : correspondence.MessageSender,
             Created = correspondence.Created,
             Recipient = correspondence.Recipient,
             ReplyOptions = correspondence.ReplyOptions ?? new List<CorrespondenceReplyOptionEntity>(),
@@ -124,11 +130,14 @@ await _correspondenceStatusRepository.AddCorrespondenceStatus(new Correspondence
             Published = correspondence.Published,
             IsConfirmationNeeded = correspondence.IsConfirmationNeeded,
             MinimumAuthenticationLevel = (int)minimumAuthLevel,
+            AuthorizedForWrite = true,
             AuthorizedForSign = true,
             DueDateTime = correspondence.DueDateTime,
             AllowDelete = true,
             Archived = correspondence.Statuses?.FirstOrDefault(s => s.Status == CorrespondenceStatus.Archived)?.StatusChanged,
-            PropertyList = correspondence.PropertyList ?? new Dictionary<string, string>()
+            Confirmed = correspondence.Statuses?.FirstOrDefault(s => s.Status == CorrespondenceStatus.Confirmed)?.StatusChanged,
+            PropertyList = correspondence.PropertyList ?? new Dictionary<string, string>(),
+            InstanceOwnerPartyId = resourceOwnerParty.PartyId
         };
         return response;
     }
diff --git a/src/Altinn.Correspondence.Application/GetCorrespondenceOverview/LegacyGetCorrespondenceOverviewResponse.cs b/src/Altinn.Correspondence.Application/GetCorrespondenceOverview/LegacyGetCorrespondenceOverviewResponse.cs
index df98e8e6..5e61a02c 100644
--- a/src/Altinn.Correspondence.Application/GetCorrespondenceOverview/LegacyGetCorrespondenceOverviewResponse.cs
+++ b/src/Altinn.Correspondence.Application/GetCorrespondenceOverview/LegacyGetCorrespondenceOverviewResponse.cs
@@ -3,12 +3,64 @@
 
 namespace Altinn.Correspondence.Application.GetCorrespondenceOverview;
 
-public class LegacyGetCorrespondenceOverviewResponse : GetCorrespondenceOverviewResponse
+public class LegacyGetCorrespondenceOverviewResponse
 {
     public bool AllowDelete { get; set; }
     public bool AuthorizedForWrite { get; set; }
     public bool AuthorizedForSign { get; set; }
     public DateTimeOffset? Archived { get; set; }
+    public DateTimeOffset? Confirmed { get; set; }
     public int MinimumAuthenticationLevel { get; set; }
-}
+    public int InstanceOwnerPartyId { get; set; }
+    public required Guid CorrespondenceId { get; set; }
 
+    public required CorrespondenceStatus Status { get; set; }
+
+    public required string StatusText { get; set; }
+
+    public required DateTimeOffset StatusChanged { get; set; }
+
+    public string SendersReference { get; set; } = string.Empty;
+
+    public string Sender { get; set; } = string.Empty;
+
+    public string MessageSender { get; set; } = string.Empty;
+
+    public DateTimeOffset Created { get; set; }
+
+    public string Recipient { get; set; } = string.Empty;
+
+    public required string Language { get; set; }
+
+    public required string MessageTitle { get; set; }
+
+    public required string MessageSummary { get; set; }
+
+    public required string MessageBody { get; set; }
+
+    public required List<CorrespondenceAttachmentEntity> Attachments { get; set; }
+
+    public List<CorrespondenceReplyOptionEntity> ReplyOptions { get; set; } = new List<CorrespondenceReplyOptionEntity>();
+
+    public List<CorrespondenceNotificationOverview> Notifications { get; set; } = new List<CorrespondenceNotificationOverview>();
+
+    public List<ExternalReferenceEntity> ExternalReferences { get; set; } = new List<ExternalReferenceEntity>();
+
+    public string ResourceId { get; set; }
+
+    public DateTimeOffset RequestedPublishTime { get; set; }
+
+    public bool IgnoreReservation { get; set; }
+
+    public bool? MarkedUnread { get; set; }
+
+    public DateTimeOffset? AllowSystemDeleteAfter { get; set; }
+
+    public DateTimeOffset? DueDateTime { get; set; }
+
+    public Dictionary<string, string> PropertyList { get; set; } = new Dictionary<string, string>();
+
+    public DateTimeOffset? Published { get; set; }
+
+    public bool IsConfirmationNeeded { get; set; }
+}
\ No newline at end of file