diff --git a/Classes/Domain/Model/Month.php b/Classes/Domain/Model/Month.php
index 1bc5102..04a6143 100644
--- a/Classes/Domain/Model/Month.php
+++ b/Classes/Domain/Model/Month.php
@@ -78,7 +78,7 @@ public function getWeeks(): array
         while ($currentDay <= $lastDay) {
             $this->weeks[] = new Week(
                 (int) $currentDay->format('W'),
-                (int) $currentDay->format('Y')
+                (int) $currentDay->format('o')
             );
 
             $currentDay = $currentDay->modify('+7 days');
diff --git a/Classes/Domain/Model/Week.php b/Classes/Domain/Model/Week.php
index f02ab53..81e1c65 100644
--- a/Classes/Domain/Model/Week.php
+++ b/Classes/Domain/Model/Week.php
@@ -80,7 +80,7 @@ public function getPreviousWeek(): Week
 
         return new self(
             (int) $newDay->format('W'),
-            (int) $newDay->format('Y')
+            (int) $newDay->format('o')
         );
     }
 
@@ -90,7 +90,7 @@ public function getNextWeek(): Week
 
         return new self(
             (int) $newDay->format('W'),
-            (int) $newDay->format('Y')
+            (int) $newDay->format('o')
         );
     }
 
diff --git a/Documentation/Changelog/1.1.1.rst b/Documentation/Changelog/1.1.1.rst
new file mode 100644
index 0000000..e837104
--- /dev/null
+++ b/Documentation/Changelog/1.1.1.rst
@@ -0,0 +1,33 @@
+1.1.1
+=====
+
+Breaking
+--------
+
+Nothing
+
+Features
+--------
+
+Nothing
+
+Fixes
+-----
+
+* Fix broken month view if last week of December is in next year.
+
+  The cause was using the wrong character in formatting the year.
+  We now switch from `Y` to `o` which will work based on the week instead of date.
+  This is necessary as we provide this year to the week,
+  and therefore need the year of the week, not day.
+
+Tasks
+-----
+
+Nothing
+
+Deprecation
+-----------
+
+Nothing
+
diff --git a/Tests/Unit/Domain/Model/MonthTest.php b/Tests/Unit/Domain/Model/MonthTest.php
index e604516..f214f63 100644
--- a/Tests/Unit/Domain/Model/MonthTest.php
+++ b/Tests/Unit/Domain/Model/MonthTest.php
@@ -138,6 +138,28 @@ public function returnsAllDaysOfTheFebruaryMonth2021(): void
         self::assertSame('2021-02-28', $result[27]->getDateTimeInstance()->format('Y-m-d'));
     }
 
+    /**
+     * @test
+     */
+    public function returnsWeeksIfLastDecemberWeekIsInNextYear(): void
+    {
+        $subject = new Month(12, 2024);
+
+        $result = $subject->getWeeks();
+
+        self::assertCount(6, $result);
+
+        $week = array_pop($result);
+        $days = $week->getDays();
+        self::assertSame('2024-12-30', $days[0]->getDateTimeInstance()->format('Y-m-d'));
+        self::assertSame('2025-01-05', $days[6]->getDateTimeInstance()->format('Y-m-d'));
+
+        $week = array_pop($result);
+        $days = $week->getDays();
+        self::assertSame('2024-12-23', $days[0]->getDateTimeInstance()->format('Y-m-d'));
+        self::assertSame('2024-12-29', $days[6]->getDateTimeInstance()->format('Y-m-d'));
+    }
+
     /**
      * @test
      */
diff --git a/ext_emconf.php b/ext_emconf.php
index 01b4dca..80d6d14 100644
--- a/ext_emconf.php
+++ b/ext_emconf.php
@@ -10,7 +10,7 @@
     'state' => 'alpha',
     'uploadfolder' => 0,
     'clearCacheOnLoad' => 0,
-    'version' => '1.1.0',
+    'version' => '1.1.1',
     'constraints' => [
         'depends' => [
             'typo3' => '*',