diff --git a/CHANGES.rst b/CHANGES.rst
index 3db0a192..cc25a79b 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -8,6 +8,15 @@ Changelog
 
 .. towncrier release notes start
 
+5.1.4 (2024-06-07)
+------------------
+
+Bug fixes:
+
+
+- Don't error out on 'Africa/Abidjan' timezone [gyst] (#393)
+
+
 5.1.3 (2024-05-30)
 ------------------
 
diff --git a/plone/app/event/ical/exporter.py b/plone/app/event/ical/exporter.py
index bd9f8156..f313903c 100644
--- a/plone/app/event/ical/exporter.py
+++ b/plone/app/event/ical/exporter.py
@@ -111,7 +111,6 @@ def add_to_zones_map(tzmap, tzid, dt):
     if tzid.lower() == "utc" or not is_datetime(dt):
         # no need to define UTC nor timezones for date objects.
         return tzmap
-    null = datetime(1, 1, 1)
     tz = pytz.timezone(tzid)
     transitions = getattr(tz, "_utc_transition_times", None)
     if not transitions:
@@ -125,7 +124,7 @@ def add_to_zones_map(tzmap, tzid, dt):
     #     datetime, which wouldn't create a match within the max-function. this
     #     way we get the maximum transition time which is smaller than the
     #     given datetime.
-    transition = max(transitions, key=lambda item: item if item <= dtzl else null)
+    transition = max(transitions, key=lambda item: item if item <= dtzl else dt.min)
 
     # get previous transition to calculate tzoffsetfrom
     idx = transitions.index(transition)
@@ -133,10 +132,10 @@ def add_to_zones_map(tzmap, tzid, dt):
     prev_transition = transitions[prev_idx]
 
     def localize(tz, dt):
-        if dt is null:
+        if dt is datetime.min:
             # dummy time, edge case
-            # (dt at beginning of all transitions, see above.)
-            return null
+            # (dt at beginning of all transitions)
+            return dt.min
         return pytz.utc.localize(dt).astimezone(tz)  # naive to utc + localize
 
     transition = localize(tz, transition)
diff --git a/plone/app/event/tests/test_icalendar.py b/plone/app/event/tests/test_icalendar.py
index c68e4ada..c3a30eb1 100644
--- a/plone/app/event/tests/test_icalendar.py
+++ b/plone/app/event/tests/test_icalendar.py
@@ -1,6 +1,7 @@
 from datetime import datetime
 from plone.app.event import base
 from plone.app.event.dx.traverser import OccurrenceTraverser as OccTravDX
+from plone.app.event.ical.exporter import add_to_zones_map
 from plone.app.event.ical.importer import ical_import
 from plone.app.event.testing import make_fake_response
 from plone.app.event.testing import PAEventDX_FUNCTIONAL_TESTING
@@ -499,3 +500,7 @@ def test_import_from_ics__sync_keep_theirs(self):
         self.assertNotEqual(desc21, desc22)
         self.assertTrue(start21 < start22)
         self.assertTrue(end21 < end22)
+
+    def test_add_to_zones_map(self):
+        tzmap = add_to_zones_map({}, "Africa/Abidjan", datetime(2013, 1, 1, 0, 0))
+        self.assertTrue("Africa/Abidjan" in tzmap)
diff --git a/setup.py b/setup.py
index 7fd5ed78..bdc8fb2c 100644
--- a/setup.py
+++ b/setup.py
@@ -3,7 +3,7 @@
 from setuptools import setup
 
 
-version = "5.1.4.dev0"
+version = "5.1.5.dev0"
 
 
 long_description = "\n\n".join(