diff --git a/CMakeLists.txt b/CMakeLists.txt
index f9af1f2cf..85a5c5bbf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -65,9 +65,9 @@ find_package(nlohmann_json 3.10.5)
 
 add_subdirectory(edm4hep)
 add_subdirectory(utils)
-add_subdirectory(test)
 add_subdirectory(tools)
 add_subdirectory(python)
+add_subdirectory(test)
 
 #--- create uninstall target ---------------------------------------------------
 include(cmake/EDM4HEPUninstall.cmake)
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index f83a6f544..4f36494bc 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -96,4 +96,12 @@ endif()
 add_subdirectory(utils)
 add_subdirectory(tools)
 
+include(ExternalData)
+list(APPEND ExternalData_URL_TEMPLATES
+  "https://key4hep.web.cern.ch:443/testFiles/EDM4hep/%(hash)"
+)
+
 add_subdirectory(backwards_compat)
+
+ExternalData_Add_Target(backward_compat_tests)
+message(STATUS "Test inputs for backwards compatibility tests are (will be) stored in " ${ExternalData_OBJECT_STORES})
diff --git a/test/backwards_compat/CMakeLists.txt b/test/backwards_compat/CMakeLists.txt
index a03b88ef3..8d82a3986 100644
--- a/test/backwards_compat/CMakeLists.txt
+++ b/test/backwards_compat/CMakeLists.txt
@@ -1,19 +1,28 @@
 add_test(NAME check_complete_file COMMAND pytest --inputfile=${CMAKE_BINARY_DIR}/test/edm4hep_example.root -v)
 set_test_env(check_complete_file)
-set_tests_properties(
-  check_complete_file
-
-  PROPERTIES
-   DEPENDS create_complete_file
-   WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+set_tests_properties(check_complete_file PROPERTIES DEPENDS create_complete_file
 )
 
 add_test(NAME check_complete_file_rntuple COMMAND pytest --inputfile=${CMAKE_BINARY_DIR}/test/edm4hep_example_rntuple.root -v)
 set_test_env(check_complete_file_rntuple)
+set_tests_properties(check_complete_file_rntuple
+  PROPERTIES DEPENDS create_complete_file_rntuple
+)
+
+ExternalData_Add_Test(backward_compat_tests
+  NAME backwards_compat_v00-99 COMMAND pytest --inputfile=DATA{${CMAKE_CURRENT_SOURCE_DIR}/input_files/edm4hep_example_v00-99_podio_v01-00-01.root})
+set_test_env(backwards_compat_v00-99)
+
+ExternalData_Add_Test(backward_compat_tests
+  NAME backwards_compat_rntuple_v00-99 COMMAND pytest --inputfile=DATA{${CMAKE_CURRENT_SOURCE_DIR}/input_files/edm4hep_example_rntuple_v00-99_podio_v01-00-01.root})
+set_test_env(backwards_compat_rntuple_v00-99)
+
 set_tests_properties(
+  check_complete_file
   check_complete_file_rntuple
+  backwards_compat_v00-99
+  backwards_compat_rntuple_v00-99
 
   PROPERTIES
-   DEPENDS create_complete_file_rntuple
-   WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
 )
diff --git a/test/backwards_compat/input_files/edm4hep_example_rntuple_v00-99_podio_v01-00-01.root.md5 b/test/backwards_compat/input_files/edm4hep_example_rntuple_v00-99_podio_v01-00-01.root.md5
new file mode 100644
index 000000000..053830daa
--- /dev/null
+++ b/test/backwards_compat/input_files/edm4hep_example_rntuple_v00-99_podio_v01-00-01.root.md5
@@ -0,0 +1 @@
+6f3e8c366c7014c2220acd94e2cd4558
diff --git a/test/backwards_compat/input_files/edm4hep_example_v00-99_podio_v01-00-01.root.md5 b/test/backwards_compat/input_files/edm4hep_example_v00-99_podio_v01-00-01.root.md5
new file mode 100644
index 000000000..58b17ba0e
--- /dev/null
+++ b/test/backwards_compat/input_files/edm4hep_example_v00-99_podio_v01-00-01.root.md5
@@ -0,0 +1 @@
+215f4db666f696e5f9ad010cc1001b05