diff --git a/FSCalendar.podspec b/FSCalendar.podspec
index 837b9b9..598ef11 100644
--- a/FSCalendar.podspec
+++ b/FSCalendar.podspec
@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
 
   s.name             = "FSCalendar"
-  s.version          = "2.5.0"
+  s.version          = "2.5.1"
   s.summary          = "A superiorly awesome iOS7+ calendar control, compatible with Objective-C and Swift."
   
   s.homepage         = "https://github.com/WenchaoD/FSCalendar"
diff --git a/FSCalendar/FSCalendarExtensions.h b/FSCalendar/FSCalendarExtensions.h
index 44d2d2c..622b09c 100644
--- a/FSCalendar/FSCalendarExtensions.h
+++ b/FSCalendar/FSCalendarExtensions.h
@@ -60,6 +60,10 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)fs_setVariable:(id)variable forKey:(NSString *)key;
 - (id)fs_variableForKey:(NSString *)key;
+
+- (void)fs_setUnsignedIntegerVariable:(NSUInteger)value forKey:(NSString *)key;
+- (NSUInteger)fs_unsignedIntegerVariableForKey:(NSString *)key;
+
 - (id)fs_performSelector:(SEL)selector withObjects:(nullable id)firstObject, ... NS_REQUIRES_NIL_TERMINATION;
 
 @end
diff --git a/FSCalendar/FSCalendarExtensions.m b/FSCalendar/FSCalendarExtensions.m
index 466a5b8..6db05eb 100644
--- a/FSCalendar/FSCalendarExtensions.m
+++ b/FSCalendar/FSCalendarExtensions.m
@@ -257,6 +257,21 @@
     return variable;
 }
 
+- (void)fs_setUnsignedIntegerVariable:(NSUInteger)value forKey:(NSString *)key
+{
+    Ivar ivar = class_getInstanceVariable([self class], key.UTF8String);
+    ((void (*)(id, Ivar, NSUInteger))object_setIvar)(self, ivar, value);
+}
+
+- (NSUInteger)fs_unsignedIntegerVariableForKey:(NSString *)key
+{
+    Ivar ivar = class_getInstanceVariable([self class], key.UTF8String);
+    ptrdiff_t offset = ivar_getOffset(ivar);
+    unsigned char *bytes = (unsigned char *)(__bridge void*)self;
+    NSUInteger value = *((NSUInteger *)(bytes+offset));
+    return value;
+}
+
 - (id)fs_performSelector:(SEL)selector withObjects:(nullable id)firstObject, ...
 {
     if (!selector) return nil;
diff --git a/FSCalendar/Info.plist b/FSCalendar/Info.plist
index fae982c..3c8acdf 100644
--- a/FSCalendar/Info.plist
+++ b/FSCalendar/Info.plist
@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>2.5.0</string>
+	<string>2.5.1</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>