diff --git a/oslo_serialization/msgpackutils.py b/oslo_serialization/msgpackutils.py
index 01003bf..e71a123 100644
--- a/oslo_serialization/msgpackutils.py
+++ b/oslo_serialization/msgpackutils.py
@@ -33,9 +33,16 @@ import functools
 import itertools
 import uuid
 from xmlrpc import client as xmlrpclib
-import zoneinfo
 
 import msgpack
+
+try:
+    import zoneinfo
+except ImportError:
+    # zoneinfo is available in Python >= 3.9
+    from pytz import timezone
+    zoneinfo = None
+
 from oslo_utils import importutils
 
 netaddr = importutils.try_import("netaddr")
@@ -236,7 +243,10 @@ class DateTimeHandler(object):
             'microsecond': dt.microsecond,
         }
         if dt.tzinfo:
-            tz = str(dt.tzinfo)
+            if zoneinfo:
+                tz = str(dt.tzinfo)
+            else:
+                tz = dt.tzinfo.tzname(None)
             dct['tz'] = tz
         return dumps(dct, registry=self._registry)
 
@@ -264,8 +274,12 @@ class DateTimeHandler(object):
                                second=dct['second'],
                                microsecond=dct['microsecond'])
         if 'tz' in dct and dct['tz']:
-            tzinfo = zoneinfo.ZoneInfo(dct['tz'])
-            dt = dt.replace(tzinfo=tzinfo)
+            if zoneinfo:
+                tzinfo = zoneinfo.ZoneInfo(dct['tz'])
+                dt = dt.replace(tzinfo=tzinfo)
+            else:
+                tzinfo = timezone(dct['tz'])
+                dt = tzinfo.localize(dt)
         return dt
 
 
diff --git a/oslo_serialization/tests/test_msgpackutils.py b/oslo_serialization/tests/test_msgpackutils.py
index 3acc70d..7558532 100644
--- a/oslo_serialization/tests/test_msgpackutils.py
+++ b/oslo_serialization/tests/test_msgpackutils.py
@@ -15,11 +15,17 @@
 import datetime
 import itertools
 from xmlrpc import client as xmlrpclib
-import zoneinfo
 
 import netaddr
 from oslotest import base as test_base
 
+try:
+    import zoneinfo
+except ImportError:
+    # zoneinfo is available in Python >= 3.9
+    from pytz import timezone
+    zoneinfo = None
+
 from oslo_serialization import msgpackutils
 from oslo_utils import uuidutils
 
@@ -145,22 +151,31 @@ class MsgPackUtilsTest(test_base.BaseTestCase):
         self.assertEqual(today, _dumps_loads(today))
 
     def test_datetime_tz_clone(self):
-        eastern = zoneinfo.ZoneInfo('US/Eastern')
         now = datetime.datetime.now()
-        e_dt = now.replace(tzinfo=eastern)
+        if zoneinfo:
+            eastern = zoneinfo.ZoneInfo('US/Eastern')
+            e_dt = now.replace(tzinfo=eastern)
+        else:
+            eastern = timezone('US/Eastern')
+            e_dt = eastern.localize(now)
         e_dt2 = _dumps_loads(e_dt)
         self.assertEqual(e_dt, e_dt2)
         self.assertEqual(e_dt.strftime(_TZ_FMT), e_dt2.strftime(_TZ_FMT))
 
     def test_datetime_tz_different(self):
-        eastern = zoneinfo.ZoneInfo('US/Eastern')
-        pacific = zoneinfo.ZoneInfo('US/Pacific')
         now = datetime.datetime.now()
-
-        now = now.replace(tzinfo=eastern)
-        e_dt = now
-        now = now.replace(tzinfo=pacific)
-        p_dt = now
+        if zoneinfo:
+            eastern = zoneinfo.ZoneInfo('US/Eastern')
+            pacific = zoneinfo.ZoneInfo('US/Pacific')
+            now = now.replace(tzinfo=eastern)
+            e_dt = now
+            now = now.replace(tzinfo=pacific)
+            p_dt = now
+        else:
+            eastern = timezone('US/Eastern')
+            pacific = timezone('US/Pacific')
+            e_dt = eastern.localize(now)
+            p_dt = pacific.localize(now)
 
         self.assertNotEqual(e_dt, p_dt)
         self.assertNotEqual(e_dt.strftime(_TZ_FMT), p_dt.strftime(_TZ_FMT))
diff --git a/releasenotes/notes/implement-zoneinfo-to-remove-pytz-c136b33bbfbfe59f.yaml b/releasenotes/notes/implement-zoneinfo-to-remove-pytz-c136b33bbfbfe59f.yaml
index 24c7d7f..167f040 100644
--- a/releasenotes/notes/implement-zoneinfo-to-remove-pytz-c136b33bbfbfe59f.yaml
+++ b/releasenotes/notes/implement-zoneinfo-to-remove-pytz-c136b33bbfbfe59f.yaml
@@ -1,6 +1,5 @@
 ---
 other:
   - |
-    Implement zoneinfo to allow us to remove pytz's dependency. zoneinfo
-    was introduced by python 3.9, and the series 2023.2 (bobcat) set py39
-    as the minimal supported runtime, so we are able to remove pytz.
+    Implement zoneinfo to allow us to remove pytz's dependency for Python 3.9
+    and 3.10
diff --git a/requirements.txt b/requirements.txt
index d31beef..b8be88c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -10,4 +10,5 @@
 pbr!=2.1.0,>=2.0.0 # Apache-2.0
 msgpack>=0.5.2 # Apache-2.0
 oslo.utils>=3.33.0 # Apache-2.0
+pytz>=2013.6 # MIT
 tzdata>=2022.4 # MIT