diff --git a/Demo.xcodeproj/project.pbxproj b/Demo.xcodeproj/project.pbxproj
index ca631a1..b91d68a 100644
--- a/Demo.xcodeproj/project.pbxproj
+++ b/Demo.xcodeproj/project.pbxproj
@@ -958,7 +958,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = "com.sample.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
-				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_SWIFT3_OBJC_INFERENCE = Default;
 				SWIFT_VERSION = 4.0;
 			};
 			name = Debug;
@@ -975,7 +975,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = "com.sample.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SWIFT_OPTIMIZATION_LEVEL = "-Owholemodule";
-				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_SWIFT3_OBJC_INFERENCE = Default;
 				SWIFT_VERSION = 4.0;
 			};
 			name = Release;
diff --git a/Library/Helper.swift b/Library/Helper.swift
index fb590f2..d6fb227 100644
--- a/Library/Helper.swift
+++ b/Library/Helper.swift
@@ -29,9 +29,9 @@ public class Helper: NSObject {
         let letters = "ABCDEFGHIJKL"
         var string = ""
         for _ in 0 ... 5 {
-            let token = UInt32(letters.characters.count)
+            let token = UInt32(letters.count)
             let letterIndex = Int(arc4random_uniform(token))
-            let firstChar = Array(letters.characters)[letterIndex]
+            let firstChar = Array(letters)[letterIndex]
             string.append(firstChar)
         }
 
diff --git a/Source/DATASource+NSFetchedResultsControllerDelegate.swift b/Source/DATASource+NSFetchedResultsControllerDelegate.swift
index e0f9a11..8533804 100644
--- a/Source/DATASource+NSFetchedResultsControllerDelegate.swift
+++ b/Source/DATASource+NSFetchedResultsControllerDelegate.swift
@@ -61,14 +61,14 @@ extension DATASource: NSFetchedResultsControllerDelegate {
                 }
                 break
             case .update:
-                if let indexPath = indexPath {
-                    if tableView.indexPathsForVisibleRows?.index(of: indexPath) != nil {
-                        if let cell = tableView.cellForRow(at: indexPath) {
-                            self.configure(cell, indexPath: indexPath)
+                if let newIndexPath = newIndexPath {
+                    if tableView.indexPathsForVisibleRows?.index(of: newIndexPath) != nil {
+                        if let cell = tableView.cellForRow(at: newIndexPath) {
+                            self.configure(cell, indexPath: newIndexPath)
                         }
 
                         if let anObject = anObject as? NSManagedObject {
-                            self.delegate?.dataSource?(self, didUpdateObject: anObject, atIndexPath: indexPath)
+                            self.delegate?.dataSource?(self, didUpdateObject: anObject, atIndexPath: newIndexPath)
                         }
                     }
                 }