Update check and comment

test/backwards_compat/CMakeLists.txt

@@ -10,10 +10,9 @@ set_tests_properties(
 )
 
 
-if (ROOT_VERSION VERSION_LESS 6.33)
-  # This input file has been written with RNTuple RC2 which is only present up
-  # to the 6.32 release series. Trying to read this with a newer version of ROOT
-  # doesn't work
+if (${ROOT_VERSION} VERSION_GREATER_EQUAL 6.34)
+  # This input file has been written with ROOT 6.34.
+  # Trying to read this with an older version of ROOT doesn't work
   ExternalData_Add_Test(backward_compat_tests
     NAME backwards_compat_rntuple_v00-99 COMMAND pytest -v --inputfile=DATA{${CMAKE_CURRENT_SOURCE_DIR}/input_files/edm4hep_example_rntuple_v00-99-01_podio_v01-02.root})
   set_test_env(backwards_compat_rntuple_v00-99)