diff --git a/src/Api/Controllers/OrganizationUsersController.cs b/src/Api/Controllers/OrganizationUsersController.cs
index 64340e3ede..b535316ec5 100644
--- a/src/Api/Controllers/OrganizationUsersController.cs
+++ b/src/Api/Controllers/OrganizationUsersController.cs
@@ -260,6 +260,17 @@ public class OrganizationUsersController : Controller
             throw new NotFoundException();
         }
 
+        var organization = await _organizationRepository.GetByIdAsync(orgGuidId);
+        if (organization == null)
+        {
+            throw new NotFoundException();
+        }
+
+        if (model.Type == OrganizationUserType.Custom && !organization.UseCustomPermissions)
+        {
+            throw new BadRequestException("To enable custom permissions the organization must be on an Enterprise 2020 plan.");
+        }
+
         var userId = _userService.GetProperUserId(User);
         await _organizationService.SaveUserAsync(model.ToOrganizationUser(organizationUser), userId.Value,
             model.Collections?.Select(c => c.ToSelectionReadOnly()));
diff --git a/src/Api/Models/Response/ProfileOrganizationResponseModel.cs b/src/Api/Models/Response/ProfileOrganizationResponseModel.cs
index 4285ae432b..e0292993b3 100644
--- a/src/Api/Models/Response/ProfileOrganizationResponseModel.cs
+++ b/src/Api/Models/Response/ProfileOrganizationResponseModel.cs
@@ -73,6 +73,7 @@ public class ProfileOrganizationResponseModel : ResponseModel
     public bool UseApi { get; set; }
     public bool UseResetPassword { get; set; }
     public bool UsersGetPremium { get; set; }
+    public bool UseCustomPermissions { get; set; }
     public bool SelfHost { get; set; }
     public int? Seats { get; set; }
     public short? MaxCollections { get; set; }
diff --git a/src/Api/Models/Response/ProfileProviderOrganizationResponseModel.cs b/src/Api/Models/Response/ProfileProviderOrganizationResponseModel.cs
index a660662fac..88c41d99c0 100644
--- a/src/Api/Models/Response/ProfileProviderOrganizationResponseModel.cs
+++ b/src/Api/Models/Response/ProfileProviderOrganizationResponseModel.cs
@@ -22,6 +22,7 @@ public class ProfileProviderOrganizationResponseModel : ProfileOrganizationRespo
         UseApi = organization.UseApi;
         UseResetPassword = organization.UseResetPassword;
         UsersGetPremium = organization.UsersGetPremium;
+        UseCustomPermissions = organization.UseCustomPermissions;
         SelfHost = organization.SelfHost;
         Seats = organization.Seats;
         MaxCollections = organization.MaxCollections;