diff --git a/tools/jfjoch_hdf5_test.cpp b/tools/jfjoch_hdf5_test.cpp
index 7457ce55..295eb35a 100644
--- a/tools/jfjoch_hdf5_test.cpp
+++ b/tools/jfjoch_hdf5_test.cpp
@@ -69,11 +69,8 @@ int main(int argc, char **argv) {
     else
         x.FilePrefix(std::getenv("HDF5DATASET_WRITE_TEST_PREFIX"));
 
-    if (std::getenv("HDF5MASTER_NEW_FORMAT") != nullptr) {
-        std::cout << "Using new format for HDF5 master file" << std::endl;
-        x.SetFileWriterFormat(FileWriterFormat::NXmxVDS);
-    } else
-        x.SetFileWriterFormat(FileWriterFormat::NXmxLegacy);
+    std::cout << "Using new format for HDF5 master file" << std::endl;
+    x.SetFileWriterFormat(FileWriterFormat::NXmxVDS);
 
     x.ImagesPerTrigger(nimages);