- add last update in PNInstallation object

Pod/Classes/PNClasses/PNInstallation.h

@@ -72,5 +72,9 @@ typedef NS_ENUM(NSInteger, PNInstallationType) {
  *  <#Description#>
  */
 @property (nonatomic, assign) NSInteger badge;
+/**
+ *  <#Description#>
+ */
+@property (nonatomic, strong) NSDate *lastUpdate;
 
 @end

Pod/Classes/PNClasses/PNInstallation.m

@@ -37,6 +37,7 @@ static bool isFirstAccess = YES;
                               @"oldDeviceToken":@"oldDeviceToken",
                               @"badge":@"badge",
                               @"localeIdentifier":@"localeIdentifier",
+                              @"lastUpdate":@"lastUpdate",
                               };
     return mapping;
 }
@@ -93,6 +94,9 @@ static bool isFirstAccess = YES;
      */
     _oldDeviceToken = _deviceToken;
     _deviceToken = ptoken;
+    if (response != PNInstallationTypeNone) {
+        _lastUpdate = [NSDate date];
+    }
     
     return response;
 }