diff --git a/src/NzbDrone.Api/Profiles/Delay/DelayProfileModule.cs b/src/NzbDrone.Api/Profiles/Delay/DelayProfileModule.cs
index 636979d86..f14e4a487 100644
--- a/src/NzbDrone.Api/Profiles/Delay/DelayProfileModule.cs
+++ b/src/NzbDrone.Api/Profiles/Delay/DelayProfileModule.cs
@@ -28,14 +28,12 @@ namespace NzbDrone.Api.Profiles.Delay
             SharedValidator.RuleFor(d => d.UsenetDelay).GreaterThanOrEqualTo(0);
             SharedValidator.RuleFor(d => d.TorrentDelay).GreaterThanOrEqualTo(0);
 
-            SharedValidator.Custom(delayProfile =>
+            SharedValidator.RuleFor(d => d).Custom((delayProfile, context) =>
             {
                 if (!delayProfile.EnableUsenet && !delayProfile.EnableTorrent)
                 {
-                    return new ValidationFailure("", "Either Usenet or Torrent should be enabled");
+                    context.AddFailure("Either Usenet or Torrent should be enabled");
                 }
-
-                return null;
             });
         }
 
diff --git a/src/NzbDrone.Api/Restrictions/RestrictionModule.cs b/src/NzbDrone.Api/Restrictions/RestrictionModule.cs
index 7188e57fb..c5c80574e 100644
--- a/src/NzbDrone.Api/Restrictions/RestrictionModule.cs
+++ b/src/NzbDrone.Api/Restrictions/RestrictionModule.cs
@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using FluentValidation;
 using FluentValidation.Results;
 using NzbDrone.Common.Extensions;
 using NzbDrone.Core.Profiles.Releases;
@@ -22,14 +23,12 @@ namespace NzbDrone.Api.Restrictions
             UpdateResource = UpdateRestriction;
             DeleteResource = DeleteRestriction;
 
-            SharedValidator.Custom(restriction =>
+            SharedValidator.RuleFor(r => r).Custom((restriction, context) =>
             {
                 if (restriction.Ignored.IsNullOrWhiteSpace() && restriction.Required.IsNullOrWhiteSpace())
                 {
-                    return new ValidationFailure("", "Either 'Must contain' or 'Must not contain' is required");
+                    context.AddFailure("Either 'Must contain' or 'Must not contain' is required");
                 }
-
-                return null;
             });
         }
 
diff --git a/src/NzbDrone.Api/Sonarr.Api.csproj b/src/NzbDrone.Api/Sonarr.Api.csproj
index 52389eeb8..c60916e61 100644
--- a/src/NzbDrone.Api/Sonarr.Api.csproj
+++ b/src/NzbDrone.Api/Sonarr.Api.csproj
@@ -4,7 +4,7 @@
     <Platforms>x86</Platforms>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="FluentValidation" Version="6.2.1.0" />
+    <PackageReference Include="FluentValidation" Version="8.4.0" />
     <PackageReference Include="Ical.Net" Version="2.2.32" />
     <PackageReference Include="Nancy" Version="1.4.4" />
     <PackageReference Include="Nancy.Authentication.Basic" Version="1.4.1" />
diff --git a/src/NzbDrone.Core/Indexers/Newznab/NewznabSettings.cs b/src/NzbDrone.Core/Indexers/Newznab/NewznabSettings.cs
index ee7bd3d9d..bd7d78c17 100644
--- a/src/NzbDrone.Core/Indexers/Newznab/NewznabSettings.cs
+++ b/src/NzbDrone.Core/Indexers/Newznab/NewznabSettings.cs
@@ -37,14 +37,12 @@ namespace NzbDrone.Core.Indexers.Newznab
 
         public NewznabSettingsValidator()
         {
-            Custom(newznab =>
+            RuleFor(c => c).Custom((c, context) =>
             {
-                if (newznab.Categories.Empty() && newznab.AnimeCategories.Empty())
+                if (c.Categories.Empty() && c.AnimeCategories.Empty())
                 {
-                    return new ValidationFailure("", "Either 'Categories' or 'Anime Categories' must be provided");
+                    context.AddFailure("Either 'Categories' or 'Anime Categories' must be provided");
                 }
-
-                return null;
             });
 
             RuleFor(c => c.BaseUrl).ValidRootUrl();
diff --git a/src/NzbDrone.Core/Indexers/Torznab/TorznabSettings.cs b/src/NzbDrone.Core/Indexers/Torznab/TorznabSettings.cs
index dc8e8eab2..476ba1932 100644
--- a/src/NzbDrone.Core/Indexers/Torznab/TorznabSettings.cs
+++ b/src/NzbDrone.Core/Indexers/Torznab/TorznabSettings.cs
@@ -30,14 +30,12 @@ namespace NzbDrone.Core.Indexers.Torznab
 
         public TorznabSettingsValidator()
         {
-            Custom(newznab =>
+            RuleFor(c => c).Custom((c, context) =>
             {
-                if (newznab.Categories.Empty() && newznab.AnimeCategories.Empty())
+                if (c.Categories.Empty() && c.AnimeCategories.Empty())
                 {
-                    return new ValidationFailure("", "Either 'Categories' or 'Anime Categories' must be provided");
+                    context.AddFailure("Either 'Categories' or 'Anime Categories' must be provided");
                 }
-
-                return null;
             });
 
             RuleFor(c => c.BaseUrl).ValidRootUrl();
diff --git a/src/NzbDrone.Core/Sonarr.Core.csproj b/src/NzbDrone.Core/Sonarr.Core.csproj
index 70f42cd39..8837b1172 100644
--- a/src/NzbDrone.Core/Sonarr.Core.csproj
+++ b/src/NzbDrone.Core/Sonarr.Core.csproj
@@ -5,7 +5,7 @@
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="FluentMigrator.Runner" Version="1.6.2" />
-    <PackageReference Include="FluentValidation" Version="6.2.1.0" />
+    <PackageReference Include="FluentValidation" Version="8.4.0" />
     <PackageReference Include="ImageResizer" Version="3.4.3" />
     <PackageReference Include="Newtonsoft.Json" Version="9.0.1" />
     <PackageReference Include="NLog" Version="4.5.3" />
diff --git a/src/NzbDrone.Test.Common/Sonarr.Test.Common.csproj b/src/NzbDrone.Test.Common/Sonarr.Test.Common.csproj
index 5220c1dec..616f6d90c 100644
--- a/src/NzbDrone.Test.Common/Sonarr.Test.Common.csproj
+++ b/src/NzbDrone.Test.Common/Sonarr.Test.Common.csproj
@@ -6,7 +6,7 @@
   <ItemGroup>
     <PackageReference Include="CommonServiceLocator" Version="1.3" />
     <PackageReference Include="FluentAssertions" Version="4.19.0" />
-    <PackageReference Include="FluentValidation" Version="6.2.1.0" />
+    <PackageReference Include="FluentValidation" Version="8.4.0" />
     <PackageReference Include="Moq" Version="4.0.10827" />
     <PackageReference Include="NLog" Version="4.5.3" />
     <PackageReference Include="NUnit" Version="3.6.0" />
diff --git a/src/Sonarr.Api.V3/Profiles/Delay/DelayProfileModule.cs b/src/Sonarr.Api.V3/Profiles/Delay/DelayProfileModule.cs
index 9613c75bd..d6f106ac9 100644
--- a/src/Sonarr.Api.V3/Profiles/Delay/DelayProfileModule.cs
+++ b/src/Sonarr.Api.V3/Profiles/Delay/DelayProfileModule.cs
@@ -32,14 +32,12 @@ namespace Sonarr.Api.V3.Profiles.Delay
             SharedValidator.RuleFor(d => d.UsenetDelay).GreaterThanOrEqualTo(0);
             SharedValidator.RuleFor(d => d.TorrentDelay).GreaterThanOrEqualTo(0);
 
-            SharedValidator.Custom(delayProfile =>
+            SharedValidator.RuleFor(d => d).Custom((delayProfile, context) =>
             {
                 if (!delayProfile.EnableUsenet && !delayProfile.EnableTorrent)
                 {
-                    return new ValidationFailure("", "Either Usenet or Torrent should be enabled");
+                    context.AddFailure("Either Usenet or Torrent should be enabled");
                 }
-
-                return null;
             });
         }
 
diff --git a/src/Sonarr.Api.V3/Profiles/Release/ReleaseProfileModule.cs b/src/Sonarr.Api.V3/Profiles/Release/ReleaseProfileModule.cs
index c87662357..9e61585c4 100644
--- a/src/Sonarr.Api.V3/Profiles/Release/ReleaseProfileModule.cs
+++ b/src/Sonarr.Api.V3/Profiles/Release/ReleaseProfileModule.cs
@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using FluentValidation;
 using FluentValidation.Results;
 using NzbDrone.Common.Extensions;
 using NzbDrone.Core.Profiles.Releases;
@@ -21,14 +22,12 @@ namespace Sonarr.Api.V3.Profiles.Release
             UpdateResource = Update;
             DeleteResource = DeleteReleaseProfile;
 
-            SharedValidator.Custom(restriction =>
+            SharedValidator.RuleFor(d => d).Custom((restriction, context) =>
             {
                 if (restriction.Ignored.IsNullOrWhiteSpace() && restriction.Required.IsNullOrWhiteSpace() && restriction.Preferred.Empty())
                 {
-                    return new ValidationFailure("", "'Must contain', 'Must not contain' or 'Preferred' is required");
+                    context.AddFailure("'Must contain', 'Must not contain' or 'Preferred' is required");
                 }
-
-                return null;
             });
         }
 
diff --git a/src/Sonarr.Api.V3/Sonarr.Api.V3.csproj b/src/Sonarr.Api.V3/Sonarr.Api.V3.csproj
index 87b9433d2..e4a1206ec 100644
--- a/src/Sonarr.Api.V3/Sonarr.Api.V3.csproj
+++ b/src/Sonarr.Api.V3/Sonarr.Api.V3.csproj
@@ -4,7 +4,7 @@
     <Platforms>x86</Platforms>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="FluentValidation" Version="6.2.1.0" />
+    <PackageReference Include="FluentValidation" Version="8.4.0" />
     <PackageReference Include="Ical.Net" Version="2.2.32" />
     <PackageReference Include="Nancy" Version="1.4.4" />
     <PackageReference Include="Nancy.Authentication.Basic" Version="1.4.1" />
diff --git a/src/Sonarr.Http/REST/ResourceValidator.cs b/src/Sonarr.Http/REST/ResourceValidator.cs
index 6f91bf8f0..4e4662ee8 100644
--- a/src/Sonarr.Http/REST/ResourceValidator.cs
+++ b/src/Sonarr.Http/REST/ResourceValidator.cs
@@ -18,7 +18,7 @@ namespace Sonarr.Http.REST
             rule.DisplayName = new StaticStringSource(fieldName);
 
             AddRule(rule);
-            return new RuleBuilder<TResource, TProperty>(rule);
+            return new RuleBuilder<TResource, TProperty>(rule, this);
         }
 
         private static object GetValue(object container, Func<TResource, IEnumerable<Field>> fieldListAccessor, string fieldName)
diff --git a/src/Sonarr.Http/Sonarr.Http.csproj b/src/Sonarr.Http/Sonarr.Http.csproj
index 90f53aa36..b03f142c3 100644
--- a/src/Sonarr.Http/Sonarr.Http.csproj
+++ b/src/Sonarr.Http/Sonarr.Http.csproj
@@ -4,7 +4,7 @@
     <Platforms>x86</Platforms>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="FluentValidation" Version="6.2.1.0" />
+    <PackageReference Include="FluentValidation" Version="8.4.0" />
     <PackageReference Include="Nancy" Version="1.4.4" />
     <PackageReference Include="Nancy.Authentication.Basic" Version="1.4.1" />
     <PackageReference Include="Nancy.Authentication.Forms" Version="1.4.1" />