diff --git a/Program.cs b/Program.cs
index ea3106d..a748178 100644
--- a/Program.cs
+++ b/Program.cs
@@ -17,17 +17,7 @@ namespace ttrss_co_client
             var apiLevel = await ttrssClient.GetApiLevel();
             Console.WriteLine($"api level: {apiLevel}");
 
-            var cats = await ttrssClient.GetCategories(include_empty: true);
-            Console.WriteLine($"{cats.Count()} categor{(cats.Count() == 1 ? "y" : "ies")} found");
-            var firstUnread = cats.FirstOrDefault(f => f.unread > 0);
-            if(firstUnread != null)
-            {
-                Console.WriteLine($"first unread: {firstUnread.title} (id {firstUnread.id})");
-            }
-            else
-            {
-                Console.WriteLine("no categories with feeds with unread articles.");
-            }
+            
 
             var loggedout = await ttrssClient.Logout();
             Console.WriteLine($"logged out: {loggedout}");
diff --git a/ttrss/ApiClient.cs b/ttrss/ApiClient.cs
index 2994a2f..2637bc0 100644
--- a/ttrss/ApiClient.cs
+++ b/ttrss/ApiClient.cs
@@ -155,7 +155,6 @@ namespace ttrss_co_client.ttrss
             var response = await (await httpClient.PostAsync(BaseURI, json)).Content.ReadAsStringAsync();
             var apiResult = JsonConvert.DeserializeObject<ApiResponse<IEnumerable<Category>>>(response);
             return apiResult.Content;
-
         }
         public enum VIEWMODE { All, Unread, Adaptive, Marked, Updated }
         public enum SORTORDER { Default, OldestFirst, NewestFirst }
@@ -300,7 +299,8 @@ namespace ttrss_co_client.ttrss
             var apiResult = JsonConvert.DeserializeObject<ApiResponse<IEnumerable<Headline>>>(response);
             return apiResult.Content;
         }
-        // public async Task<HeadlinesHeaderResponse> GetHeadlinesAndHeader(
+        #region Get headlines include_header=true
+        // public async Task<Tuple<ttrss.messages.HeadlinesHeaderResponse, IEnumerable<Headline>>> GetHeadlinesAndHeader(
         //     int feed_id,
         //     bool is_cat,
         //     int limit=60,
@@ -418,25 +418,63 @@ namespace ttrss_co_client.ttrss
         //     });
         //     return await getHeadlinesAndHeader(json);
         // }
-        // private async Task<HeadlinesHeaderResponse> getHeadlinesAndHeader(JsonContent parameters)
+
+        //todo: deserialize array of disparate types. can that be done?
+        // private async Task<Tuple<ttrss.messages.HeadlinesHeaderResponse, IEnumerable<Headline>>> getHeadlinesAndHeader(JsonContent parameters)
         // {
         //     var response = await (await httpClient.PostAsync(BaseURI, parameters)).Content.ReadAsStringAsync();
-        //     var apiResult = JsonConvert.DeserializeObject<ttrss.messages.HeadlinesHeaderResponse>(response);
+        //     var immediateApiResult = JsonConvert.DeserializeObject<ApiResponse<IEnumerable<string>>>(response).Content.ToList();
+        //     var apiResult = JsonConvert.DeserializeObject<Tuple<ttrss.messages.HeadlinesHeaderResponse, IEnumerable<Headline>>>(immediateApiResult[1]);
         //     return apiResult;
         // }
-        public enum UPDATEMODE { SetFalse, SetTrue, Toggle }
-        public enum UPDATEFIELD { starred, published, unread }
+        #endregion
+        public enum UPDATEMODE { SetFalse=0, SetTrue=1, Toggle=2 }
+        ///<summary>to update note, see <see cref="UpdateArticleNote"/></summary>
+        public enum UPDATEFIELD { starred=0, published=1, unread=2 }
         public async Task<int> UpdateArticleField(UPDATEMODE mode, UPDATEFIELD field, params int[] ids)
         {
+            if(ids == null || ids.Length == 0)
+            {
+                throw new System.ArgumentNullException("ids", "need to specify at least one id");
+            }
             //documentation: UpdateArticle - for note, we have a separate method UpdateArticleNote
             assertInitialized();
+
+            var json = JsonContent.Create(new
+            {
+                op = "updateArticle",
+                sid = this.SessionId,
+                article_ids = string.Join(',', ids),
+                mode = (int)mode,
+                field = (int)field
+            });
+            var response = await (await httpClient.PostAsync(BaseURI, json)).Content.ReadAsStringAsync();
+            var apiResult = JsonConvert.DeserializeObject<ApiResponse<ArticleUpdateFieldResponse>>(response);
+            return apiResult.Content.updated;
+
             throw new NotImplementedException();
         }
+        ///<summary>for fields other than note, we have a separate method UpdateArticleField</summary>
         public async Task<int> UpdateArticleNote(string data, params int[] ids)
         {
-            //documentation: UpdateArticle - for fields other than note, we have a separate method UpdateArticleField
+            if(ids == null || ids.Length == 0)
+            {
+                throw new System.ArgumentNullException("ids", "need to specify at least one id");
+            }
+            //documentation: UpdateArticle - for note, we have a separate method UpdateArticleNote
             assertInitialized();
-            throw new NotImplementedException();
+
+            var json = JsonContent.Create(new
+            {
+                op = "updateArticle",
+                sid = this.SessionId,
+                article_ids = string.Join(',', ids),
+                field = 3,
+                data = data,
+            });
+            var response = await (await httpClient.PostAsync(BaseURI, json)).Content.ReadAsStringAsync();
+            var apiResult = JsonConvert.DeserializeObject<ApiResponse<ArticleUpdateFieldResponse>>(response);
+            return apiResult.Content.updated;
         }
         public async Task<IEnumerable<object>> GetArticle(params int[] article_id)
         {
diff --git a/ttrss/messages/ArticleUpdateFieldResponse.cs b/ttrss/messages/ArticleUpdateFieldResponse.cs
new file mode 100644
index 0000000..ef964df
--- /dev/null
+++ b/ttrss/messages/ArticleUpdateFieldResponse.cs
@@ -0,0 +1,10 @@
+using ttrss_co_client.ttrss.datastructures;
+
+namespace ttrss_co_client.ttrss.messages
+{
+    public class ArticleUpdateFieldResponse
+    {
+        public string status {get;set;}
+        public int updated { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/ttrss/messages/HeadlinesHeaderResponse.cs b/ttrss/messages/HeadlinesHeaderResponse.cs
index d02ae4d..d5af94a 100644
--- a/ttrss/messages/HeadlinesHeaderResponse.cs
+++ b/ttrss/messages/HeadlinesHeaderResponse.cs
@@ -2,7 +2,7 @@ using ttrss_co_client.ttrss.datastructures;
 
 namespace ttrss_co_client.ttrss.messages
 {
-    public class HeadlinesHeaderContent
+    public class HeadlinesHeaderResponse
     {
         public int id { get; set; }
         public int first_id { get; set; }