diff --git a/src/ria_toolkit_oss/io/recording.py b/src/ria_toolkit_oss/io/recording.py
index 94d7bc2..f162be6 100644
--- a/src/ria_toolkit_oss/io/recording.py
+++ b/src/ria_toolkit_oss/io/recording.py
@@ -267,6 +267,13 @@ def to_sigmf(
         SigMFFile.DATATYPE_KEY: get_data_type_str(samples),
         SigMFFile.VERSION_KEY: sigmf.__version__,
         SigMFFile.RECORDER_KEY: "RIA",
+        SigMFFile.EXTENSIONS_KEY: [
+            {
+                "name": "ria",
+                "version": "0.1.4",
+                "optional": True,
+            }
+        ],
     }
 
     converted_metadata = {