diff --git a/AltBeacon/Source/AltBeacon.h b/AltBeacon/Source/AltBeacon.h
index cf5953d..efe3439 100644
--- a/AltBeacon/Source/AltBeacon.h
+++ b/AltBeacon/Source/AltBeacon.h
@@ -54,6 +54,7 @@ typedef enum {
 
 @property (nonatomic, readonly) BOOL isDetecting;
 @property (nonatomic, readonly) BOOL isBroadcasting;
+@property (nonatomic, readonly) NSString* identifier;
 
 - (void)startDetecting;
 - (void)stopDetecting;
diff --git a/AltBeacon/Source/AltBeacon.m b/AltBeacon/Source/AltBeacon.m
index b1871b0..dafd298 100644
--- a/AltBeacon/Source/AltBeacon.m
+++ b/AltBeacon/Source/AltBeacon.m
@@ -49,11 +49,10 @@
 #define ALT_BEACON_CHARACTERISTIC @"A05F9DF4-9D54-4600-9224-983B75B9D154"
 
 @interface AltBeacon () <CBPeripheralManagerDelegate, CBCentralManagerDelegate, CBPeripheralDelegate>
+@property (nonatomic, readwrite) NSString* identifier;
 @end
 
 @implementation AltBeacon {
-    NSString *identifier;
-
     CBCentralManager *centralManager;
     CBPeripheralManager *peripheralManager;
 
@@ -76,7 +75,7 @@ @implementation AltBeacon {
 
 - (id)initWithIdentifier:(NSString *)theIdentifier {
     if ((self = [super init])) {
-        identifier = theIdentifier;
+        self.identifier = theIdentifier;
 
         uuidsDetected = [[NSMutableDictionary alloc] init];
         peripheralDetected = [[NSMutableDictionary alloc] init];
@@ -176,11 +175,11 @@ - (void)startDetectingBeacons {
 
 
 - (void)             peripheral:(CBPeripheral *)peripheral
-didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic
+didUpdateValueForCharacteristic:(CBCharacteristic *)peripheralCharacteristic
                           error:(NSError *)error {
 
     if (!error) {
-        NSData *data = characteristic.value;
+        NSData *data = peripheralCharacteristic.value;
         NSString *newStr = [[NSString alloc] initWithData:data
                                                  encoding:NSUTF8StringEncoding];
 
@@ -314,7 +313,7 @@ - (void)startAdvertising {
             [CBUUID UUIDWithString:ALT_BEACON_CHARACTERISTIC];
 
     CBMutableService *service = [[CBMutableService alloc] initWithType:altBeaconServiceUUID primary:YES];
-    NSString *strUUID = identifier;
+    NSString *strUUID = self.identifier;
     NSData *dataUUID = [strUUID dataUsingEncoding:NSUTF8StringEncoding];
 
     characteristic =
diff --git a/AltBeacon/Source/Extension/NSDate+Ext.m b/AltBeacon/Source/Extension/NSDate+Ext.m
index a5a6a17..955363a 100644
--- a/AltBeacon/Source/Extension/NSDate+Ext.m
+++ b/AltBeacon/Source/Extension/NSDate+Ext.m
@@ -42,30 +42,30 @@ - (BOOL)extHasExpired {
 }
 
 - (NSUInteger)extMonth {
-    NSDateComponents *components = [[NSCalendar currentCalendar] components:NSMonthCalendarUnit fromDate:self];
+    NSDateComponents *components = [[NSCalendar currentCalendar] components:NSCalendarUnitMonth fromDate:self];
     return components.month;
 }
 
 - (NSUInteger)extDay {
-    NSDateComponents *components = [[NSCalendar currentCalendar] components:NSDayCalendarUnit fromDate:self];
+    NSDateComponents *components = [[NSCalendar currentCalendar] components:NSCalendarUnitDay fromDate:self];
     return components.day;
 }
 
 - (NSUInteger)extYear {
-    NSDateComponents *components = [[NSCalendar currentCalendar] components:NSYearCalendarUnit fromDate:self];
+    NSDateComponents *components = [[NSCalendar currentCalendar] components:NSCalendarUnitYear fromDate:self];
     return components.year;
 }
 
 - (NSUInteger)extDaysInMonth {
-    NSRange days = [[NSCalendar currentCalendar] rangeOfUnit:NSDayCalendarUnit
-                                                      inUnit:NSMonthCalendarUnit
+    NSRange days = [[NSCalendar currentCalendar] rangeOfUnit:NSCalendarUnitDay
+                                                      inUnit:NSCalendarUnitMonth
                                                      forDate:self];
 
     return days.length;
 }
 
 - (NSUInteger)extWeekday {
-    NSDateComponents *components = [[NSCalendar currentCalendar] components:NSWeekdayCalendarUnit fromDate:self];
+    NSDateComponents *components = [[NSCalendar currentCalendar] components:NSCalendarUnitWeekday fromDate:self];
     return components.weekday;
 }
 
@@ -73,7 +73,8 @@ + (NSArray *)extGenerateMonthsFromDate:(NSDate *)fromDate toDate:(NSDate *)toDat
     NSMutableArray *months = [[NSMutableArray alloc] init];
     [months addObject:fromDate];
 
-    NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
+    
+    NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
     NSDateComponents *offsetComponents = [[NSDateComponents alloc] init];
     [offsetComponents setMonth:1];
     
@@ -87,7 +88,7 @@ + (NSArray *)extGenerateMonthsFromDate:(NSDate *)fromDate toDate:(NSDate *)toDat
 }
 
 - (NSUInteger)extLastDayOfMonth {
-    NSRange daysRange = [[NSCalendar currentCalendar] rangeOfUnit:NSDayCalendarUnit inUnit:NSMonthCalendarUnit forDate:self];
+    NSRange daysRange = [[NSCalendar currentCalendar] rangeOfUnit:NSCalendarUnitDay inUnit:NSCalendarUnitMonth forDate:self];
     
     return daysRange.length;
 }
diff --git a/AltBeacon/Source/Extension/NSFileManager+Ext.h b/AltBeacon/Source/Extension/NSFileManager+Ext.h
index 9010dc0..9b29dbd 100644
--- a/AltBeacon/Source/Extension/NSFileManager+Ext.h
+++ b/AltBeacon/Source/Extension/NSFileManager+Ext.h
@@ -7,6 +7,7 @@
 //
 
 #import <Foundation/Foundation.h>
+@import CoreGraphics;
 
 @interface NSFileManager(Ext)
 - (CGFloat)extFileSizeInMegaBytesAtPath:(NSString *)path;
diff --git a/AltBeacon/Source/Extension/NSString+Ext.h b/AltBeacon/Source/Extension/NSString+Ext.h
index 8d5a643..362b484 100644
--- a/AltBeacon/Source/Extension/NSString+Ext.h
+++ b/AltBeacon/Source/Extension/NSString+Ext.h
@@ -5,6 +5,8 @@
 //  Copyright (c) 2011 Ben Ford All rights reserved.
 //
 
+@import CoreGraphics;
+@import UIKit;
 #import <Foundation/Foundation.h>
 
 typedef enum {
diff --git a/AltBeacon/Source/Util/EasedValue.h b/AltBeacon/Source/Util/EasedValue.h
index 25dc07b..518650e 100644
--- a/AltBeacon/Source/Util/EasedValue.h
+++ b/AltBeacon/Source/Util/EasedValue.h
@@ -26,7 +26,7 @@
 //  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 //  THE SOFTWARE.
 
-
+@import CoreGraphics;
 #import <Foundation/Foundation.h>
 
 /**
diff --git a/AltBeacon/Source/Util/EasedValue.m b/AltBeacon/Source/Util/EasedValue.m
index 5e613e8..1d631ae 100644
--- a/AltBeacon/Source/Util/EasedValue.m
+++ b/AltBeacon/Source/Util/EasedValue.m
@@ -68,7 +68,7 @@ - (void)update
     currentValue += velocity;
     
     // limit how small the ease can get
-    if(fabsf(targetValue - currentValue) < 0.001f){
+    if(fabs(targetValue - currentValue) < 0.001f){
         currentValue = targetValue;
         velocity = 0.0f;
     }