diff --git a/shard.yml b/shard.yml
index 0b8a273..32889c8 100644
--- a/shard.yml
+++ b/shard.yml
@@ -1,5 +1,5 @@
 name: office365
-version: 1.21.1
+version: 1.21.2
 
 crystal: ">= 0.36.1"
 
diff --git a/src/models/recurrence_pattern.cr b/src/models/recurrence_pattern.cr
index 4ae4770..4efcb07 100644
--- a/src/models/recurrence_pattern.cr
+++ b/src/models/recurrence_pattern.cr
@@ -55,7 +55,7 @@ module Office365
     property month : Int32?
     property type : RecurrencePatternType?
 
-    def initialize(@type, @interval = nil, @days_of_week = nil, @first_day_of_week = nil, @day_of_month = nil, @index = nil, @month = nil)
+    def initialize(@type, @interval = nil, @days_of_week = nil, @first_day_of_week = DayOfWeek::Sunday, @day_of_month = nil, @index = nil, @month = nil)
     end
   end
 end