diff --git a/Control/DataModelTest/DataModelTestDataRead/DataModelTestDataRead/versions/AllocTestAuxContainer_v1.h b/Control/DataModelTest/DataModelTestDataRead/DataModelTestDataRead/versions/AllocTestAuxContainer_v1.h
index a98e01cc3592aceb683b0825b7204b2dc6c314d2..4cbe6df4dcea89db5ab554655c4a01ea8999d8e8 100644
--- a/Control/DataModelTest/DataModelTestDataRead/DataModelTestDataRead/versions/AllocTestAuxContainer_v1.h
+++ b/Control/DataModelTest/DataModelTestDataRead/DataModelTestDataRead/versions/AllocTestAuxContainer_v1.h
@@ -1,6 +1,6 @@
 // This file's extension implies that it's C, but it's really -*- C++ -*-.
 /*
-  Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
  */
 /**
  * @file DataModelTestDataRead/versions/AllocTestAuxContainer_v1.h
@@ -41,10 +41,10 @@ public:
 
 
   // For this one, the dictionary will always be present (from AthContainers).
-  std::vector<int, std::pmr::polymorphic_allocator<int> > atInt1;
+  AUXVAR_DECL (int, atInt1, std::pmr::polymorphic_allocator);
 
   // For this one, the dictionary is only present in this package.
-  std::vector<int, Athena_test::TestAlloc<int> > atInt2;
+  AUXVAR_DECL (int, atInt2, Athena_test::TestAlloc);
 };
 
 
diff --git a/Control/DataModelTest/DataModelTestDataRead/DataModelTestDataRead/versions/GAuxContainer_v1.h b/Control/DataModelTest/DataModelTestDataRead/DataModelTestDataRead/versions/GAuxContainer_v1.h
index ad7f94908a8ff94617ec22919720f80ea9a37c4c..1cdfdddaf8978c5c3314d2e634f717b3a3bf53e7 100644
--- a/Control/DataModelTest/DataModelTestDataRead/DataModelTestDataRead/versions/GAuxContainer_v1.h
+++ b/Control/DataModelTest/DataModelTestDataRead/DataModelTestDataRead/versions/GAuxContainer_v1.h
@@ -1,7 +1,7 @@
 // This file's extension implies that it's C, but it's really -*- C++ -*-.
 
 /*
-  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
 */
 /**
  * @file DataModelTestDataRead/versions/GAuxContainer_v1.h
@@ -31,9 +31,9 @@ public:
   GAuxContainer_v1();
 
 private:
-  SG::PackedContainer<int> anInt;
-  std::vector<float> gFloat;
-  std::vector<std::vector<float> > gvFloat;
+  AUXVAR_PACKEDCONTAINER_DECL (int, anInt);
+  AUXVAR_DECL (float, gFloat);
+  AUXVAR_DECL (std::vector<float>, gvFloat);
 };
 
 
diff --git a/Control/DataModelTest/DataModelTestDataRead/DataModelTestDataRead/versions/HAuxContainer_v1.h b/Control/DataModelTest/DataModelTestDataRead/DataModelTestDataRead/versions/HAuxContainer_v1.h
index 99a6bfc1d5ce7d76161ec8072ffc64857331d454..ddf79caac3ca5fbf0cddaaa3e202080e2eae2a01 100644
--- a/Control/DataModelTest/DataModelTestDataRead/DataModelTestDataRead/versions/HAuxContainer_v1.h
+++ b/Control/DataModelTest/DataModelTestDataRead/DataModelTestDataRead/versions/HAuxContainer_v1.h
@@ -1,11 +1,8 @@
 // This file's extension implies that it's C, but it's really -*- C++ -*-.
-
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
 */
-
-// $Id$
-/**
+/*
  * @file DataModelTestDataRead/versions/HAuxContainer_v1.h
  * @author scott snyder <snyder@bnl.gov>
  * @date Jan, 2016
@@ -32,7 +29,7 @@ public:
   HAuxContainer_v1();
 
 private:
-  std::vector<int> anInt;
+  AUXVAR_DECL (int, anInt);
 };
 
 
diff --git a/Control/DataModelTest/DataModelTestDataRead/DataModelTestDataRead/versions/HAuxContainer_v2.h b/Control/DataModelTest/DataModelTestDataRead/DataModelTestDataRead/versions/HAuxContainer_v2.h
index 20678abf68246c227890326e13091385ee1ecd74..81b35c88b094aa460309281b14374e102f90268a 100644
--- a/Control/DataModelTest/DataModelTestDataRead/DataModelTestDataRead/versions/HAuxContainer_v2.h
+++ b/Control/DataModelTest/DataModelTestDataRead/DataModelTestDataRead/versions/HAuxContainer_v2.h
@@ -1,10 +1,7 @@
 // This file's extension implies that it's C, but it's really -*- C++ -*-.
-
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
 */
-
-// $Id$
 /**
  * @file DataModelTestDataRead/versions/HAuxContainer_v2.h
  * @author scott snyder <snyder@bnl.gov>
@@ -33,7 +30,7 @@ public:
   HAuxContainer_v2();
 
 private:
-  std::vector<float> aFloat;
+  AUXVAR_DECL (float, aFloat);
 };
 
 
diff --git a/Control/DataModelTest/DataModelTestDataRead/src/AllocTestAuxContainer_v1.cxx b/Control/DataModelTest/DataModelTestDataRead/src/AllocTestAuxContainer_v1.cxx
index d2af1efdd90c92a7c8de54bf3d631fffb12d3a90..24a03d84ff4f632593b72f94f0d72f6999d929e3 100644
--- a/Control/DataModelTest/DataModelTestDataRead/src/AllocTestAuxContainer_v1.cxx
+++ b/Control/DataModelTest/DataModelTestDataRead/src/AllocTestAuxContainer_v1.cxx
@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
 */
 /**
  * @file DataModelTestDataRead/src/AllocTestAuxContainer_v1.cxx
@@ -64,11 +64,8 @@ namespace DMTest {
 
 
 AllocTestAuxContainer_v1::AllocTestAuxContainer_v1()
-  : xAOD::AuxContainerBase(),
-    atInt1 (&memRes)
+  : xAOD::AuxContainerBase(&memRes)
 {
-  AUX_VARIABLE (atInt1);
-  AUX_VARIABLE (atInt2);
 }
 
 
diff --git a/Control/DataModelTest/DataModelTestDataRead/src/GAuxContainer_v1.cxx b/Control/DataModelTest/DataModelTestDataRead/src/GAuxContainer_v1.cxx
index d10fccdede2990ec378a0e5266c5aa18013bbbb0..4b44bc714b202666223a3298341f43d6213ebd46 100644
--- a/Control/DataModelTest/DataModelTestDataRead/src/GAuxContainer_v1.cxx
+++ b/Control/DataModelTest/DataModelTestDataRead/src/GAuxContainer_v1.cxx
@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
 */
 /**
  * @file DataModelTestDataRead/src/GAuxContainer_v1.cxx
@@ -20,15 +20,10 @@ namespace DMTest {
 GAuxContainer_v1::GAuxContainer_v1()
   : xAOD::AuxContainerBase()
 {
-  AUX_VARIABLE (anInt);
-
   if (!anInt.setOption (SG::AuxDataOption ("nbits", 17)))
   {
     throw std::runtime_error ("Can't set packing options in GAuxContainer_v1");
   }
-
-  AUX_VARIABLE (gFloat);
-  AUX_VARIABLE (gvFloat);
 }
 
 
diff --git a/Control/DataModelTest/DataModelTestDataRead/src/HAuxContainer_v1.cxx b/Control/DataModelTest/DataModelTestDataRead/src/HAuxContainer_v1.cxx
index 21327ba5194cf07fdad232bc71c35500f755a6ae..8e7eac4e79a168d5912aa2fecef45dfa9ea1ec28 100644
--- a/Control/DataModelTest/DataModelTestDataRead/src/HAuxContainer_v1.cxx
+++ b/Control/DataModelTest/DataModelTestDataRead/src/HAuxContainer_v1.cxx
@@ -1,8 +1,6 @@
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
 */
-
-// $Id$
 /**
  * @file DataModelTestDataRead/src/HAuxContainer_v1.cxx
  * @author scott snyder <snyder@bnl.gov>
@@ -20,7 +18,6 @@ namespace DMTest {
 HAuxContainer_v1::HAuxContainer_v1()
   : xAOD::AuxContainerBase()
 {
-  AUX_VARIABLE (anInt);
 }
 
 
diff --git a/Control/DataModelTest/DataModelTestDataRead/src/HAuxContainer_v2.cxx b/Control/DataModelTest/DataModelTestDataRead/src/HAuxContainer_v2.cxx
index 212e3cc50b6d7b05562921e785709d9cbe1cca49..e6b6a977d3cb7182fcd1d7a546b9bef40f457d18 100644
--- a/Control/DataModelTest/DataModelTestDataRead/src/HAuxContainer_v2.cxx
+++ b/Control/DataModelTest/DataModelTestDataRead/src/HAuxContainer_v2.cxx
@@ -1,8 +1,6 @@
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
 */
-
-// $Id$
 /**
  * @file DataModelTestDataRead/src/HAuxContainer_v2.cxx
  * @author scott snyder <snyder@bnl.gov>
@@ -20,7 +18,6 @@ namespace DMTest {
 HAuxContainer_v2::HAuxContainer_v2()
   : xAOD::AuxContainerBase()
 {
-  AUX_VARIABLE (aFloat);
 }