diff --git a/source/Octopus.Client.Tests/PublicSurfaceAreaFixture.ThePublicSurfaceAreaShouldNotRegress..NETCore.approved.txt b/source/Octopus.Client.Tests/PublicSurfaceAreaFixture.ThePublicSurfaceAreaShouldNotRegress..NETCore.approved.txt
index 718b11efb..f3ebb1e24 100644
--- a/source/Octopus.Client.Tests/PublicSurfaceAreaFixture.ThePublicSurfaceAreaShouldNotRegress..NETCore.approved.txt
+++ b/source/Octopus.Client.Tests/PublicSurfaceAreaFixture.ThePublicSurfaceAreaShouldNotRegress..NETCore.approved.txt
@@ -7299,8 +7299,8 @@ Octopus.Client.Model.TenantVariables
 {
   class CommonVariableScope
   {
-    .ctor(String[])
-    String[] EnvironmentIds { get; set; }
+    .ctor(Octopus.Client.Model.ReferenceCollection)
+    Octopus.Client.Model.ReferenceCollection EnvironmentIds { get; set; }
   }
   class GetCommonVariablesByTenantIdRequest
   {
@@ -7354,8 +7354,8 @@ Octopus.Client.Model.TenantVariables
   }
   class ProjectVariableScope
   {
-    .ctor(String[])
-    String[] EnvironmentIds { get; set; }
+    .ctor(Octopus.Client.Model.ReferenceCollection)
+    Octopus.Client.Model.ReferenceCollection EnvironmentIds { get; set; }
   }
   class TenantCommonVariable
   {
diff --git a/source/Octopus.Client.Tests/PublicSurfaceAreaFixture.ThePublicSurfaceAreaShouldNotRegress..NETFramework.approved.txt b/source/Octopus.Client.Tests/PublicSurfaceAreaFixture.ThePublicSurfaceAreaShouldNotRegress..NETFramework.approved.txt
index 67770d5b5..700f26e89 100644
--- a/source/Octopus.Client.Tests/PublicSurfaceAreaFixture.ThePublicSurfaceAreaShouldNotRegress..NETFramework.approved.txt
+++ b/source/Octopus.Client.Tests/PublicSurfaceAreaFixture.ThePublicSurfaceAreaShouldNotRegress..NETFramework.approved.txt
@@ -7323,8 +7323,8 @@ Octopus.Client.Model.TenantVariables
 {
   class CommonVariableScope
   {
-    .ctor(String[])
-    String[] EnvironmentIds { get; set; }
+    .ctor(Octopus.Client.Model.ReferenceCollection)
+    Octopus.Client.Model.ReferenceCollection EnvironmentIds { get; set; }
   }
   class GetCommonVariablesByTenantIdRequest
   {
@@ -7378,8 +7378,8 @@ Octopus.Client.Model.TenantVariables
   }
   class ProjectVariableScope
   {
-    .ctor(String[])
-    String[] EnvironmentIds { get; set; }
+    .ctor(Octopus.Client.Model.ReferenceCollection)
+    Octopus.Client.Model.ReferenceCollection EnvironmentIds { get; set; }
   }
   class TenantCommonVariable
   {
diff --git a/source/Octopus.Server.Client/Model/TenantVariables/ModifyCommonVariablesByTenantIdCommand.cs b/source/Octopus.Server.Client/Model/TenantVariables/ModifyCommonVariablesByTenantIdCommand.cs
index c6044ed25..981fb960d 100644
--- a/source/Octopus.Server.Client/Model/TenantVariables/ModifyCommonVariablesByTenantIdCommand.cs
+++ b/source/Octopus.Server.Client/Model/TenantVariables/ModifyCommonVariablesByTenantIdCommand.cs
@@ -23,9 +23,9 @@ public class TenantCommonVariable(string libraryVariableSetId, string templateId
     public CommonVariableScope Scope { get; set; } = scope;
 }
 
-public class CommonVariableScope(string[] environmentIds)
+public class CommonVariableScope(ReferenceCollection environmentIds)
 {
-    public string[] EnvironmentIds { get; set; } = environmentIds;
+    public ReferenceCollection EnvironmentIds { get; set; } = environmentIds;
 }
 
 public class ModifyCommonVariablesByTenantIdResponse(string tenantId, TenantCommonVariable[] commonVariables)
@@ -33,4 +33,4 @@ public class ModifyCommonVariablesByTenantIdResponse(string tenantId, TenantComm
     public string TenantId { get; set; } = tenantId;
         
     public TenantCommonVariable[] CommonVariables { get; set; } = commonVariables;
-}
\ No newline at end of file
+}
diff --git a/source/Octopus.Server.Client/Model/TenantVariables/ModifyProjectVariablesByTenantIdCommand.cs b/source/Octopus.Server.Client/Model/TenantVariables/ModifyProjectVariablesByTenantIdCommand.cs
index 1e48eba9b..9b8031e8f 100644
--- a/source/Octopus.Server.Client/Model/TenantVariables/ModifyProjectVariablesByTenantIdCommand.cs
+++ b/source/Octopus.Server.Client/Model/TenantVariables/ModifyProjectVariablesByTenantIdCommand.cs
@@ -26,9 +26,9 @@ public class TenantProjectVariable(
     public ProjectVariableScope Scope { get; set; } = scope;
 }
 
-public class ProjectVariableScope(string[] environmentIds)
+public class ProjectVariableScope(ReferenceCollection environmentIds)
 {
-    public string[] EnvironmentIds { get; set; } = environmentIds;
+    public ReferenceCollection EnvironmentIds { get; set; } = environmentIds;
 }
 
 public class ModifyProjectVariablesByTenantIdResponse(string tenantId, TenantProjectVariable[] projectVariables)