diff --git a/mapcat/toolkit/act.py b/mapcat/toolkit/act.py
index a671c9d..d4cdf92 100644
--- a/mapcat/toolkit/act.py
+++ b/mapcat/toolkit/act.py
@@ -18,9 +18,22 @@ def extract_string(input: bytes) -> str:
 
 def parse_info_file(path: Path) -> dict:
     with h5py.File(path, "r") as f:
-        return {
-            "frequency": extract_string(f["band"][...])[1:],
-            "tube_slot": extract_string(f["detset"][...]),
+        if 'band' in f and 'detset' in f:
+            ## backward compatibility with old SO format
+            return {
+                "frequency": extract_string(f["band"][...])[1:],
+                "tube_slot": extract_string(f["detset"][...]),
+                "observations": [extract_string(x) for x in f["ids"][...]],
+                "start_time": f["period"][0],
+                "stop_time": f["period"][1],
+                "ctime": float(f["t"][...]),
+                "box": f["box"][...],
+            }
+        else:
+            ## ACT depth1 format.
+            return {
+            "frequency": extract_string(f["array"][...]).split('_')[1],
+            "tube_slot": extract_string(f["array"][...]).split('_')[0],
             "observations": [extract_string(x) for x in f["ids"][...]],
             "start_time": f["period"][0],
             "stop_time": f["period"][1],
@@ -28,7 +41,6 @@ def parse_info_file(path: Path) -> dict:
             "box": f["box"][...],
         }
 
-
 def parse_filenames(base: str, relative_to: Path) -> dict[str, str]:
     """
     Parse a base filename (e.g. /path/base/18234/depth1_182341234_i1_f090)