diff --git a/pyproject.toml b/pyproject.toml
index a5211ba5..1f2f54e7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -43,6 +43,7 @@ dependencies = [
     "yt>=4.0.1",
     # https://github.com/scipy/oldest-supported-numpy/issues/76#issuecomment-1628865694
     "numpy>=1.17.5,<2.0",
+    "packaging>=20.9",
 ]
 
 [project.readme]
diff --git a/yt_astro_analysis/cosmological_observation/light_cone/light_cone_projection.py b/yt_astro_analysis/cosmological_observation/light_cone/light_cone_projection.py
index 3001e124..6c6eca6b 100644
--- a/yt_astro_analysis/cosmological_observation/light_cone/light_cone_projection.py
+++ b/yt_astro_analysis/cosmological_observation/light_cone/light_cone_projection.py
@@ -13,15 +13,24 @@
 # The full license is in the file COPYING.txt, distributed with this software.
 # -----------------------------------------------------------------------------
 
+from importlib.metadata import version
+
 import numpy as np
+from packaging.version import Version
 
 from yt.funcs import mylog
-from yt.units.yt_array import uconcatenate
 from yt.utilities.parallel_tools.parallel_analysis_interface import (
     parallel_blocking_call,
 )
 from yt.visualization.fixed_resolution import FixedResolutionBuffer
 
+_UNYT_VERSION = Version(version("unyt"))
+
+if _UNYT_VERSION >= Version("3.0"):
+    uconcatenate = np.concatenate
+else:
+    from unyt.array import uconcatenate
+
 
 @parallel_blocking_call
 def _light_cone_projection(