diff --git a/BTCPayServer.Client/BTCPayServer.Client.csproj b/BTCPayServer.Client/BTCPayServer.Client.csproj
index 7522bd9e2..4acef7f94 100644
--- a/BTCPayServer.Client/BTCPayServer.Client.csproj
+++ b/BTCPayServer.Client/BTCPayServer.Client.csproj
@@ -5,7 +5,8 @@
     </PropertyGroup>
 
     <ItemGroup>
-      <PackageReference Include="System.Text.Json" Version="4.7.1" />
+      <PackageReference Include="NBitcoin" Version="5.0.20" />
+      <PackageReference Include="Newtonsoft.Json" Version="12.0.3" />
     </ItemGroup>
 
 </Project>
diff --git a/BTCPayServer.Client/BTCPayServerClient.cs b/BTCPayServer.Client/BTCPayServerClient.cs
index 60c81c400..d3780411c 100644
--- a/BTCPayServer.Client/BTCPayServerClient.cs
+++ b/BTCPayServer.Client/BTCPayServerClient.cs
@@ -5,23 +5,25 @@ using System.Linq;
 using System.Net.Http;
 using System.Net.Http.Headers;
 using System.Text;
-using System.Text.Json;
 using System.Threading.Tasks;
+using Newtonsoft.Json;
 
 namespace BTCPayServer.Client
 {
     public partial class BTCPayServerClient
     {
+        static BTCPayServerClient()
+        {
+            _GlobalSerializer = new JsonSerializerSettings();
+            Serializer.RegisterConverters(_GlobalSerializer);
+        }
         private readonly string _apiKey;
         private readonly Uri _btcpayHost;
         private readonly HttpClient _httpClient;
 
         public string APIKey => _apiKey;
 
-        private readonly JsonSerializerOptions _serializerOptions = new JsonSerializerOptions()
-        {
-            PropertyNamingPolicy = JsonNamingPolicy.CamelCase
-        };
+        private static readonly JsonSerializerSettings _GlobalSerializer = new JsonSerializerSettings();
 
         public BTCPayServerClient(Uri btcpayHost, HttpClient httpClient = null)
         {
@@ -45,7 +47,7 @@ namespace BTCPayServer.Client
         protected async Task<T> HandleResponse<T>(HttpResponseMessage message)
         {
             HandleResponse(message);
-            return JsonSerializer.Deserialize<T>(await message.Content.ReadAsStringAsync(), _serializerOptions);
+            return JsonConvert.DeserializeObject<T>(await message.Content.ReadAsStringAsync(), _GlobalSerializer);
         }
 
         protected virtual HttpRequestMessage CreateHttpRequest(string path,
@@ -73,7 +75,7 @@ namespace BTCPayServer.Client
             var request = CreateHttpRequest(path, queryPayload, method);
             if (typeof(T).IsPrimitive || !EqualityComparer<T>.Default.Equals(bodyPayload, default(T)))
             {
-                request.Content = new StringContent(JsonSerializer.Serialize(bodyPayload, _serializerOptions), Encoding.UTF8, "application/json");
+                request.Content = new StringContent(JsonConvert.SerializeObject(bodyPayload, _GlobalSerializer), Encoding.UTF8, "application/json");
             }
 
             return request;
diff --git a/BTCPayServer.Client/JsonConverters/PermissionJsonConverter.cs b/BTCPayServer.Client/JsonConverters/PermissionJsonConverter.cs
new file mode 100644
index 000000000..26bf1eace
--- /dev/null
+++ b/BTCPayServer.Client/JsonConverters/PermissionJsonConverter.cs
@@ -0,0 +1,34 @@
+using System;
+using System.Reflection;
+using System.Collections.Generic;
+using System.Text;
+using Newtonsoft.Json;
+using NBitcoin.JsonConverters;
+
+namespace BTCPayServer.Client.JsonConverters
+{
+    public class PermissionJsonConverter : JsonConverter
+    {
+        public override bool CanConvert(Type objectType)
+        {
+            return typeof(Permission).GetTypeInfo().IsAssignableFrom(objectType.GetTypeInfo());
+        }
+
+        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+        {
+            if (reader.TokenType == JsonToken.Null)
+                return null;
+            if (reader.TokenType != JsonToken.String)
+                throw new JsonObjectException("Type 'Permission' is expected to be a 'String'", reader);
+            if (reader.ReadAsString() is String s && Permission.TryParse(s, out var permission))
+                return permission;
+            throw new JsonObjectException("Invalid 'Permission' String", reader);
+        }
+
+        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        {
+            if (value is Permission v)
+                writer.WriteValue(v.ToString());
+        }
+    }
+}
diff --git a/BTCPayServer.Client/Models/ApiKeyData.cs b/BTCPayServer.Client/Models/ApiKeyData.cs
index 58872cb11..244859f60 100644
--- a/BTCPayServer.Client/Models/ApiKeyData.cs
+++ b/BTCPayServer.Client/Models/ApiKeyData.cs
@@ -5,6 +5,6 @@ namespace BTCPayServer.Client.Models
         public string ApiKey { get; set; }
         public string Label { get; set; }
         public string UserId { get; set; }
-        public string[] Permissions { get; set; }
+        public Permission[] Permissions { get; set; }
     }
 }
diff --git a/BTCPayServer.Client/Permissions.cs b/BTCPayServer.Client/Permissions.cs
index 1dfa845c0..88adc5389 100644
--- a/BTCPayServer.Client/Permissions.cs
+++ b/BTCPayServer.Client/Permissions.cs
@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Text.Json.Serialization;
 
 namespace BTCPayServer.Client
 {
diff --git a/BTCPayServer.Client/Serializer.cs b/BTCPayServer.Client/Serializer.cs
new file mode 100644
index 000000000..7ab7b43b4
--- /dev/null
+++ b/BTCPayServer.Client/Serializer.cs
@@ -0,0 +1,18 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using BTCPayServer.Client.JsonConverters;
+using Newtonsoft.Json;
+
+namespace BTCPayServer.Client
+{
+    public class Serializer
+    {
+        public static void RegisterConverters(JsonSerializerSettings settings)
+        {
+            if (settings == null)
+                throw new ArgumentNullException(nameof(settings));
+            settings.Converters.Add(new PermissionJsonConverter());
+        }
+    }
+}
diff --git a/BTCPayServer.Tests/ApiKeysTests.cs b/BTCPayServer.Tests/ApiKeysTests.cs
index ee7c64f4d..fde2e5433 100644
--- a/BTCPayServer.Tests/ApiKeysTests.cs
+++ b/BTCPayServer.Tests/ApiKeysTests.cs
@@ -165,7 +165,7 @@ namespace BTCPayServer.Tests
             var expectedPermissions = Permission.ToPermissions(expectedPermissionsString).ToArray();
             expectedPermissions ??= new Permission[0];
             var apikeydata = await TestApiAgainstAccessToken<ApiKeyData>(accessToken, $"api/v1/api-keys/current", tester.PayTester.HttpClient);
-            var permissions = Permission.ToPermissions(apikeydata.Permissions).ToArray();
+            var permissions = apikeydata.Permissions;
             Assert.Equal(expectedPermissions.Length, permissions.Length);
             foreach (var expectPermission in expectedPermissions)
             {
diff --git a/BTCPayServer/Controllers/ManageController.APIKeys.cs b/BTCPayServer/Controllers/ManageController.APIKeys.cs
index 8a2429ed6..169a8b48e 100644
--- a/BTCPayServer/Controllers/ManageController.APIKeys.cs
+++ b/BTCPayServer/Controllers/ManageController.APIKeys.cs
@@ -331,7 +331,6 @@ namespace BTCPayServer.Controllers
             }
             public string Label { get; set; }
             public StoreData[] Stores { get; set; }
-            ApiKeyStoreMode _StoreMode;
             public ApiKeyStoreMode StoreMode { get; set; }
             public List<string> SpecificStores { get; set; } = new List<string>();
             public PermissionValueItem StoreManagementPermission { get; set; }
diff --git a/BTCPayServer/Controllers/RestApi/ApiKeys/ApiKeysController.cs b/BTCPayServer/Controllers/RestApi/ApiKeys/ApiKeysController.cs
index cc7b7e7de..ea2dc4ff2 100644
--- a/BTCPayServer/Controllers/RestApi/ApiKeys/ApiKeysController.cs
+++ b/BTCPayServer/Controllers/RestApi/ApiKeys/ApiKeysController.cs
@@ -45,7 +45,7 @@ namespace BTCPayServer.Controllers.RestApi.ApiKeys
         {
             return new ApiKeyData()
             {
-                Permissions = Permission.ToPermissions(data.Permissions).Select(c => c.ToString()).ToArray(),
+                Permissions = Permission.ToPermissions(data.Permissions).ToArray(),
                 ApiKey = data.Id,
                 UserId = data.UserId,
                 Label = data.Label
diff --git a/BTCPayServer/Controllers/StoresController.BTCLike.cs b/BTCPayServer/Controllers/StoresController.BTCLike.cs
index eebebf054..44d7d7370 100644
--- a/BTCPayServer/Controllers/StoresController.BTCLike.cs
+++ b/BTCPayServer/Controllers/StoresController.BTCLike.cs
@@ -387,7 +387,7 @@ namespace BTCPayServer.Controllers
 
         private async Task<bool> CanUseHotWallet()
         {
-            var isAdmin = (await _authorizationService.AuthorizeAsync(User, Permission.CanModifyServerSettings)).Succeeded;
+            var isAdmin = (await _authorizationService.AuthorizeAsync(User, Policies.CanModifyServerSettings)).Succeeded;
             if (isAdmin)
                 return true;
             var policies = await _settingsRepository.GetSettingAsync<PoliciesSettings>();
diff --git a/BTCPayServer/Controllers/VaultController.cs b/BTCPayServer/Controllers/VaultController.cs
index edb4211a3..c07c59794 100644
--- a/BTCPayServer/Controllers/VaultController.cs
+++ b/BTCPayServer/Controllers/VaultController.cs
@@ -128,7 +128,7 @@ namespace BTCPayServer.Controllers
                                 }
                                 await websocketHelper.Send("{ \"info\": \"ready\"}", cancellationToken);
                                 o = JObject.Parse(await websocketHelper.NextMessageAsync(cancellationToken));
-                                var authorization = await _authorizationService.AuthorizeAsync(User, Permission.CanModifyStoreSettings);
+                                var authorization = await _authorizationService.AuthorizeAsync(User, Policies.CanModifyStoreSettings);
                                 if (!authorization.Succeeded)
                                 {
                                     await websocketHelper.Send("{ \"error\": \"not-authorized\"}", cancellationToken);
diff --git a/BTCPayServer/Security/APIKeys/APIKeyAuthorizationHandler.cs b/BTCPayServer/Security/APIKeys/APIKeyAuthorizationHandler.cs
index 0c06c5760..a4306ff37 100644
--- a/BTCPayServer/Security/APIKeys/APIKeyAuthorizationHandler.cs
+++ b/BTCPayServer/Security/APIKeys/APIKeyAuthorizationHandler.cs
@@ -36,13 +36,13 @@ namespace BTCPayServer.Security.APIKeys
             bool success = false;
             switch (requirement.Policy)
             {
-                case Permission.CanModifyProfile:
-                case Permission.CanViewProfile:
+                case Policies.CanModifyProfile:
+                case Policies.CanViewProfile:
                     success = context.HasPermission(Permission.Create(requirement.Policy));
                     break;
 
-                case Permission.CanViewStoreSettings:
-                case Permission.CanModifyStoreSettings:
+                case Policies.CanViewStoreSettings:
+                case Policies.CanModifyStoreSettings:
                     var storeId = _HttpContext.GetImplicitStoreId();
                     var userid = _userManager.GetUserId(context.User);
                     // Specific store action
@@ -72,8 +72,8 @@ namespace BTCPayServer.Security.APIKeys
                         success = true;
                     }
                     break;
-                case Permission.CanCreateUser:
-                case Permission.CanModifyServerSettings:
+                case Policies.CanCreateUser:
+                case Policies.CanModifyServerSettings:
                     if (context.HasPermission(Permission.Create(requirement.Policy)))
                     {
                         var user = await _userManager.GetUserAsync(context.User);
diff --git a/BTCPayServer/Security/Bitpay/BitpayAuthorizationHandler.cs b/BTCPayServer/Security/Bitpay/BitpayAuthorizationHandler.cs
index 30b100e14..6183eeeab 100644
--- a/BTCPayServer/Security/Bitpay/BitpayAuthorizationHandler.cs
+++ b/BTCPayServer/Security/Bitpay/BitpayAuthorizationHandler.cs
@@ -55,7 +55,7 @@ namespace BTCPayServer.Security.Bitpay
             var anyoneCanInvoice = store.GetStoreBlob().AnyoneCanInvoice;
             switch (requirement.Policy)
             {
-                case Permission.CanCreateInvoice:
+                case Policies.CanCreateInvoice:
                     if (!isAnonymous || (isAnonymous && anyoneCanInvoice))
                     {
                         context.Succeed(requirement);
@@ -63,7 +63,7 @@ namespace BTCPayServer.Security.Bitpay
                         return;
                     }
                     break;
-                case Policies.CanGetRates.Key:
+                case ServerPolicies.CanGetRates.Key:
                     context.Succeed(requirement);
                     _HttpContext.SetStoreData(store);
                     return;
diff --git a/BTCPayServer/Security/CookieAuthorizationHandler.cs b/BTCPayServer/Security/CookieAuthorizationHandler.cs
index 9f5c5e603..d2546dc22 100644
--- a/BTCPayServer/Security/CookieAuthorizationHandler.cs
+++ b/BTCPayServer/Security/CookieAuthorizationHandler.cs
@@ -36,7 +36,7 @@ namespace BTCPayServer.Security
             var isAdmin = context.User.IsInRole(Roles.ServerAdmin);
             switch (requirement.Policy)
             {
-                case Permission.CanModifyServerSettings:
+                case Policies.CanModifyServerSettings:
                     if (isAdmin)
                         context.Succeed(requirement);
                     return;
@@ -57,11 +57,11 @@ namespace BTCPayServer.Security
             bool success = false;
             switch (requirement.Policy)
             {
-                case Permission.CanModifyStoreSettings:
+                case Policies.CanModifyStoreSettings:
                     if (store.Role == StoreRoles.Owner || isAdmin)
                         success = true;
                     break;
-                case Permission.CanCreateInvoice:
+                case Policies.CanCreateInvoice:
                     if (store.Role == StoreRoles.Owner ||
                         store.Role == StoreRoles.Guest ||
                         isAdmin ||