diff --git a/pyproject.toml b/pyproject.toml
index f2ab531..41975c6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -20,7 +20,7 @@ dynamic = ["version"]
 requires-python = ">=3.9"
 dependencies = [
     "numpy",
-    "protozfits",
+    "protozfits~=2.4",
     "ctapipe~=0.20.0",
 ]
 
diff --git a/src/ctapipe_io_zfits/conftest.py b/src/ctapipe_io_zfits/conftest.py
index 203f76c..4e96b8b 100644
--- a/src/ctapipe_io_zfits/conftest.py
+++ b/src/ctapipe_io_zfits/conftest.py
@@ -7,8 +7,8 @@
 import pytest
 from astropy.time import Time
 from ctapipe.containers import EventType
-from protozfits import CTA_DL0_Subarray_pb2 as DL0_Subarray
-from protozfits import CTA_DL0_Telescope_pb2 as DL0_Telescope
+from protozfits import DL0v1_Subarray_pb2 as DL0_Subarray
+from protozfits import DL0v1_Telescope_pb2 as DL0_Telescope
 from protozfits import ProtobufZOFits
 from protozfits.CoreMessages_pb2 import AnyArray
 
@@ -120,7 +120,7 @@ def dummy_dl0(dl0_base):
         num_samples_nominal=40,
         num_samples_long=0,
         num_modules=265,
-        sampling_frequncy=1024,
+        sampling_frequency=1024,
     )
 
     time = obs_start