diff --git a/doc/source/whatsnew/v0.24.0.rst b/doc/source/whatsnew/v0.24.0.rst
index 6066f0ec44147..9889f1ee3c1db 100644
--- a/doc/source/whatsnew/v0.24.0.rst
+++ b/doc/source/whatsnew/v0.24.0.rst
@@ -1026,7 +1026,7 @@ Deprecations
 - The ``fastpath`` keyword of the different Index constructors is deprecated (:issue:`23110`).
 - :meth:`Timestamp.tz_localize`, :meth:`DatetimeIndex.tz_localize`, and :meth:`Series.tz_localize` have deprecated the ``errors`` argument in favor of the ``nonexistent`` argument (:issue:`8917`)
 - The class ``FrozenNDArray`` has been deprecated. When unpickling, ``FrozenNDArray`` will be unpickled to ``np.ndarray`` once this class is removed (:issue:`9031`)
-- The method :meth:`DataFrame.update` has deprecated the ``raise_conflict=False|True`` keyword in favor of ``errors='ignore'|'raise'`` (:issue:`23585`)
+- The methods :meth:`DataFrame.update` and :meth:`Panel.update` have deprecated the ``raise_conflict=False|True`` keyword in favor of ``errors='ignore'|'raise'`` (:issue:`23585`)
 - Deprecated the `nthreads` keyword of :func:`pandas.read_feather` in favor of
   `use_threads` to reflect the changes in pyarrow 0.11.0. (:issue:`23053`)
 - :func:`pandas.read_excel` has deprecated accepting ``usecols`` as an integer. Please pass in a list of ints from 0 to ``usecols`` inclusive instead (:issue:`23527`)
diff --git a/pandas/tests/test_panel.py b/pandas/tests/test_panel.py
index 0e45fd6411ac0..522141da1015c 100644
--- a/pandas/tests/test_panel.py
+++ b/pandas/tests/test_panel.py
@@ -2358,6 +2358,7 @@ def test_update_raise_on_overlap(self):
                      [[1.5, np.nan, 3.], [1.5, np.nan, 3.],
                       [1.5, np.nan, 3.],
                       [1.5, np.nan, 3.]]])
+        other = Panel([[[]]])
 
         with pytest.raises(ValueError, match='Data overlaps'):
             pan.update(pan, errors='raise')