diff --git a/src/NzbDrone.Core.Test/Datastore/Migration/040_newznab_category_to_capabilities_settingsFixture.cs b/src/NzbDrone.Core.Test/Datastore/Migration/040_newznab_category_to_capabilities_settingsFixture.cs
new file mode 100644
index 000000000..b51bf6433
--- /dev/null
+++ b/src/NzbDrone.Core.Test/Datastore/Migration/040_newznab_category_to_capabilities_settingsFixture.cs
@@ -0,0 +1,200 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using FluentAssertions;
+using Newtonsoft.Json.Linq;
+using NUnit.Framework;
+using NzbDrone.Common.Serializer;
+using NzbDrone.Core.Datastore.Migration;
+using NzbDrone.Core.Test.Framework;
+
+namespace NzbDrone.Core.Test.Datastore.Migration
+{
+    [TestFixture]
+    public class newznab_category_to_capabilities_settingsFixture : MigrationTest<newznab_category_to_capabilities_settings>
+    {
+        [Test]
+        public void should_migrate_categories_when_capabilities_is_not_defined()
+        {
+            var db = WithMigrationTestDb(c =>
+            {
+                c.Insert.IntoTable("Indexers").Row(new
+                {
+                    Name = "Usenet Indexer",
+                    Redirect = false,
+                    AppProfileId = 0,
+                    DownloadClientId = 0,
+                    Priority = 25,
+                    Added = DateTime.UtcNow,
+                    Implementation = "Newznab",
+                    Settings = new
+                    {
+                        Categories = new[]
+                        {
+                            new { Id = 2000, Name = "Movies" },
+                            new { Id = 5000, Name = "TV" }
+                        }
+                    }.ToJson(),
+                    ConfigContract = "NewznabSettings"
+                });
+            });
+
+            var items = db.Query<IndexerDefinition40>("SELECT \"Id\", \"Implementation\", \"ConfigContract\", \"Settings\" FROM \"Indexers\"");
+
+            items.Should().HaveCount(1);
+            items.First().Implementation.Should().Be("Newznab");
+            items.First().ConfigContract.Should().Be("NewznabSettings");
+            items.First().Settings.Should().ContainKey("capabilities");
+            items.First().Settings.Should().NotContainKey("categories");
+
+            var newznabSettings = items.First().Settings.ToObject<NewznabSettings40>();
+            newznabSettings.Capabilities.Should().NotBeNull();
+            newznabSettings.Capabilities.SupportsRawSearch.Should().Be(false);
+            newznabSettings.Capabilities.Categories.Should().HaveCount(2);
+            newznabSettings.Capabilities.Categories.Should().Contain(c => c.Id == 2000 && c.Name == "Movies");
+            newznabSettings.Capabilities.Categories.Should().Contain(c => c.Id == 5000 && c.Name == "TV");
+        }
+
+        [Test]
+        public void should_migrate_categories_when_capabilities_is_defined()
+        {
+            var db = WithMigrationTestDb(c =>
+            {
+                c.Insert.IntoTable("Indexers").Row(new
+                {
+                    Name = "Usenet Indexer",
+                    Redirect = false,
+                    AppProfileId = 0,
+                    DownloadClientId = 0,
+                    Priority = 25,
+                    Added = DateTime.UtcNow,
+                    Implementation = "Newznab",
+                    Settings = new
+                    {
+                        Capabilities = new
+                        {
+                            SupportsRawSearch = true
+                        },
+                        Categories = new[]
+                        {
+                            new { Id = 2000, Name = "Movies" },
+                            new { Id = 5000, Name = "TV" }
+                        }
+                    }.ToJson(),
+                    ConfigContract = "NewznabSettings"
+                });
+            });
+
+            var items = db.Query<IndexerDefinition40>("SELECT \"Id\", \"Implementation\", \"ConfigContract\", \"Settings\" FROM \"Indexers\"");
+
+            items.Should().HaveCount(1);
+            items.First().Implementation.Should().Be("Newznab");
+            items.First().ConfigContract.Should().Be("NewznabSettings");
+            items.First().Settings.Should().ContainKey("capabilities");
+            items.First().Settings.Should().NotContainKey("categories");
+
+            var newznabSettings = items.First().Settings.ToObject<NewznabSettings40>();
+            newznabSettings.Capabilities.Should().NotBeNull();
+            newznabSettings.Capabilities.SupportsRawSearch.Should().Be(true);
+            newznabSettings.Capabilities.Categories.Should().HaveCount(2);
+            newznabSettings.Capabilities.Categories.Should().Contain(c => c.Id == 2000 && c.Name == "Movies");
+            newznabSettings.Capabilities.Categories.Should().Contain(c => c.Id == 5000 && c.Name == "TV");
+        }
+
+        [Test]
+        public void should_use_defaults_when_categories_are_empty()
+        {
+            var db = WithMigrationTestDb(c =>
+            {
+                c.Insert.IntoTable("Indexers").Row(new
+                {
+                    Name = "Usenet Indexer",
+                    Redirect = false,
+                    AppProfileId = 0,
+                    DownloadClientId = 0,
+                    Priority = 25,
+                    Added = DateTime.UtcNow,
+                    Implementation = "Newznab",
+                    Settings = new
+                    {
+                        Categories = Array.Empty<object>()
+                    }.ToJson(),
+                    ConfigContract = "NewznabSettings"
+                });
+            });
+
+            var items = db.Query<IndexerDefinition40>("SELECT \"Id\", \"Implementation\", \"ConfigContract\", \"Settings\" FROM \"Indexers\"");
+
+            items.Should().HaveCount(1);
+            items.First().Implementation.Should().Be("Newznab");
+            items.First().ConfigContract.Should().Be("NewznabSettings");
+            items.First().Settings.Should().ContainKey("capabilities");
+            items.First().Settings.Should().NotContainKey("categories");
+
+            var newznabSettings = items.First().Settings.ToObject<NewznabSettings40>();
+            newznabSettings.Capabilities.Should().NotBeNull();
+            newznabSettings.Capabilities.SupportsRawSearch.Should().Be(false);
+            newznabSettings.Capabilities.Categories.Should().NotBeNull();
+            newznabSettings.Capabilities.Categories.Should().HaveCount(0);
+        }
+
+        [Test]
+        public void should_use_defaults_when_settings_are_empty()
+        {
+            var db = WithMigrationTestDb(c =>
+            {
+                c.Insert.IntoTable("Indexers").Row(new
+                {
+                    Name = "Usenet Indexer",
+                    Redirect = false,
+                    AppProfileId = 0,
+                    DownloadClientId = 0,
+                    Priority = 25,
+                    Added = DateTime.UtcNow,
+                    Implementation = "Newznab",
+                    Settings = new { }.ToJson(),
+                    ConfigContract = "NewznabSettings"
+                });
+            });
+
+            var items = db.Query<IndexerDefinition40>("SELECT \"Id\", \"Implementation\", \"ConfigContract\", \"Settings\" FROM \"Indexers\"");
+
+            items.Should().HaveCount(1);
+            items.First().Implementation.Should().Be("Newznab");
+            items.First().ConfigContract.Should().Be("NewznabSettings");
+            items.First().Settings.Should().NotContainKey("capabilities");
+            items.First().Settings.Should().NotContainKey("categories");
+            items.First().Settings.ToObject<NewznabSettings40>().Capabilities.Should().BeNull();
+        }
+    }
+
+    public class IndexerDefinition40
+    {
+        public int Id { get; set; }
+        public string Implementation { get; set; }
+        public string ConfigContract { get; set; }
+        public JObject Settings { get; set; }
+    }
+
+    public class NewznabSettings39
+    {
+        public object Categories { get; set; }
+    }
+
+    public class NewznabSettings40
+    {
+        public NewznabCapabilitiesSettings40 Capabilities { get; set; }
+    }
+
+    public class NewznabCapabilitiesSettings40
+    {
+        public bool SupportsRawSearch { get; set; }
+        public List<IndexerCategory40> Categories { get; set; }
+    }
+
+    public class IndexerCategory40
+    {
+        public int Id { get; set; }
+        public string Name { get; set; }
+    }
+}
diff --git a/src/NzbDrone.Core/Datastore/Migration/040_newznab_category_to_capabilities_settings.cs b/src/NzbDrone.Core/Datastore/Migration/040_newznab_category_to_capabilities_settings.cs
new file mode 100644
index 000000000..ad573bd9c
--- /dev/null
+++ b/src/NzbDrone.Core/Datastore/Migration/040_newznab_category_to_capabilities_settings.cs
@@ -0,0 +1,65 @@
+using System.Collections.Generic;
+using System.Data;
+using Dapper;
+using FluentMigrator;
+using Newtonsoft.Json.Linq;
+using NzbDrone.Common.Serializer;
+using NzbDrone.Core.Datastore.Migration.Framework;
+
+namespace NzbDrone.Core.Datastore.Migration
+{
+    [Migration(40)]
+    public class newznab_category_to_capabilities_settings : NzbDroneMigrationBase
+    {
+        protected override void MainDbUpgrade()
+        {
+            Execute.WithConnection(MoveCategoriesToCapabilities);
+        }
+
+        private void MoveCategoriesToCapabilities(IDbConnection conn, IDbTransaction tran)
+        {
+            var updated = new List<object>();
+
+            using (var cmd = conn.CreateCommand())
+            {
+                cmd.Transaction = tran;
+                cmd.CommandText = "SELECT \"Id\", \"Settings\" FROM \"Indexers\" WHERE \"Implementation\" IN ('Newznab', 'Torznab')";
+
+                using (var reader = cmd.ExecuteReader())
+                {
+                    while (reader.Read())
+                    {
+                        var id = reader.GetInt32(0);
+                        var settings = Json.Deserialize<JObject>(reader.GetString(1));
+
+                        if ((settings.Value<JObject>("capabilities")?.ContainsKey("categories") ?? false) == false
+                            && settings.ContainsKey("categories")
+                            && settings.TryGetValue("categories", out var categories))
+                        {
+                            if (!settings.ContainsKey("capabilities"))
+                            {
+                                settings.Add("capabilities", new JObject());
+                            }
+
+                            settings.Value<JObject>("capabilities")?.Add(new JProperty("categories", JArray.FromObject(categories)));
+
+                            if (settings.ContainsKey("categories"))
+                            {
+                                settings.Remove("categories");
+                            }
+                        }
+
+                        updated.Add(new
+                        {
+                            Settings = settings.ToJson(),
+                            Id = id
+                        });
+                    }
+                }
+            }
+
+            var updateSql = "UPDATE \"Indexers\" SET \"Settings\" = @Settings WHERE \"Id\" = @Id";
+            conn.Execute(updateSql, updated, transaction: tran);
+        }
+    }
+}
diff --git a/src/NzbDrone.Core/Indexers/Definitions/Newznab/Newznab.cs b/src/NzbDrone.Core/Indexers/Definitions/Newznab/Newznab.cs
index e7109f504..bea5a92be 100644
--- a/src/NzbDrone.Core/Indexers/Definitions/Newznab/Newznab.cs
+++ b/src/NzbDrone.Core/Indexers/Definitions/Newznab/Newznab.cs
@@ -61,26 +61,23 @@ namespace NzbDrone.Core.Indexers.Newznab
         {
             var caps = new IndexerCapabilities();
 
-            if (Definition == null || Settings?.Capabilities == null)
+            if (Definition == null || Settings?.Capabilities?.Categories == null)
             {
                 return caps;
             }
 
-            caps.SupportsRawSearch = Settings.Capabilities?.SupportsRawSearch ?? false;
-            caps.SearchParams = Settings.Capabilities?.SearchParams ?? new List<SearchParam> { SearchParam.Q };
-            caps.TvSearchParams = Settings.Capabilities?.TvSearchParams ?? new List<TvSearchParam>();
-            caps.MovieSearchParams = Settings.Capabilities?.MovieSearchParams ?? new List<MovieSearchParam>();
-            caps.MusicSearchParams = Settings.Capabilities?.MusicSearchParams ?? new List<MusicSearchParam>();
-            caps.BookSearchParams = Settings.Capabilities?.BookSearchParams ?? new List<BookSearchParam>();
-
-            if (Settings.Capabilities?.Categories != null)
+            foreach (var category in Settings.Capabilities.Categories)
             {
-                foreach (var category in Settings.Capabilities.Categories)
-                {
-                    caps.Categories.AddCategoryMapping(category.Name, category);
-                }
+                caps.Categories.AddCategoryMapping(category.Name, category);
             }
 
+            caps.SupportsRawSearch = Settings?.Capabilities?.SupportsRawSearch ?? false;
+            caps.SearchParams = Settings?.Capabilities?.SearchParams ?? new List<SearchParam> { SearchParam.Q };
+            caps.TvSearchParams = Settings?.Capabilities?.TvSearchParams ?? new List<TvSearchParam>();
+            caps.MovieSearchParams = Settings?.Capabilities?.MovieSearchParams ?? new List<MovieSearchParam>();
+            caps.MusicSearchParams = Settings?.Capabilities?.MusicSearchParams ?? new List<MusicSearchParam>();
+            caps.BookSearchParams = Settings?.Capabilities?.BookSearchParams ?? new List<BookSearchParam>();
+
             return caps;
         }
 
diff --git a/src/NzbDrone.Core/Indexers/Definitions/Newznab/NewznabCapabilitiesSettings.cs b/src/NzbDrone.Core/Indexers/Definitions/Newznab/NewznabCapabilitiesSettings.cs
index 244d1c869..ed59797af 100644
--- a/src/NzbDrone.Core/Indexers/Definitions/Newznab/NewznabCapabilitiesSettings.cs
+++ b/src/NzbDrone.Core/Indexers/Definitions/Newznab/NewznabCapabilitiesSettings.cs
@@ -6,17 +6,17 @@ public class NewznabCapabilitiesSettings
 {
     public bool SupportsRawSearch { get; set; }
 
-    public List<SearchParam> SearchParams { get; set; } = new ();
+    public List<SearchParam> SearchParams { get; set; }
 
-    public List<TvSearchParam> TvSearchParams { get; set; } = new ();
+    public List<TvSearchParam> TvSearchParams { get; set; }
 
-    public List<MovieSearchParam> MovieSearchParams { get; set; } = new ();
+    public List<MovieSearchParam> MovieSearchParams { get; set; }
 
-    public List<MusicSearchParam> MusicSearchParams { get; set; } = new ();
+    public List<MusicSearchParam> MusicSearchParams { get; set; }
 
-    public List<BookSearchParam> BookSearchParams { get; set; } = new ();
+    public List<BookSearchParam> BookSearchParams { get; set; }
 
-    public List<IndexerCategory> Categories { get; set; } = new ();
+    public List<IndexerCategory> Categories { get; set; }
 
     public NewznabCapabilitiesSettings()
     {
diff --git a/src/NzbDrone.Core/Indexers/Definitions/Torznab/Torznab.cs b/src/NzbDrone.Core/Indexers/Definitions/Torznab/Torznab.cs
index 049fec0b1..42008100f 100644
--- a/src/NzbDrone.Core/Indexers/Definitions/Torznab/Torznab.cs
+++ b/src/NzbDrone.Core/Indexers/Definitions/Torznab/Torznab.cs
@@ -61,26 +61,23 @@ namespace NzbDrone.Core.Indexers.Torznab
         {
             var caps = new IndexerCapabilities();
 
-            if (Definition == null || Settings?.Capabilities == null)
+            if (Definition == null || Settings?.Capabilities?.Categories == null)
             {
                 return caps;
             }
 
-            caps.SupportsRawSearch = Settings.Capabilities?.SupportsRawSearch ?? false;
-            caps.SearchParams = Settings.Capabilities?.SearchParams ?? new List<SearchParam> { SearchParam.Q };
-            caps.TvSearchParams = Settings.Capabilities?.TvSearchParams ?? new List<TvSearchParam>();
-            caps.MovieSearchParams = Settings.Capabilities?.MovieSearchParams ?? new List<MovieSearchParam>();
-            caps.MusicSearchParams = Settings.Capabilities?.MusicSearchParams ?? new List<MusicSearchParam>();
-            caps.BookSearchParams = Settings.Capabilities?.BookSearchParams ?? new List<BookSearchParam>();
-
-            if (Settings.Capabilities?.Categories != null)
+            foreach (var category in Settings.Capabilities.Categories)
             {
-                foreach (var category in Settings.Capabilities.Categories)
-                {
-                    caps.Categories.AddCategoryMapping(category.Name, category);
-                }
+                caps.Categories.AddCategoryMapping(category.Name, category);
             }
 
+            caps.SupportsRawSearch = Settings?.Capabilities?.SupportsRawSearch ?? false;
+            caps.SearchParams = Settings?.Capabilities?.SearchParams ?? new List<SearchParam> { SearchParam.Q };
+            caps.TvSearchParams = Settings?.Capabilities?.TvSearchParams ?? new List<TvSearchParam>();
+            caps.MovieSearchParams = Settings?.Capabilities?.MovieSearchParams ?? new List<MovieSearchParam>();
+            caps.MusicSearchParams = Settings?.Capabilities?.MusicSearchParams ?? new List<MusicSearchParam>();
+            caps.BookSearchParams = Settings?.Capabilities?.BookSearchParams ?? new List<BookSearchParam>();
+
             return caps;
         }