diff --git a/Podfile b/Podfile
index 0fa5735..bfa6ae7 100644
--- a/Podfile
+++ b/Podfile
@@ -4,6 +4,6 @@ pod 'SDWebImage'
 pod 'SVProgressHUD'
 pod 'SVPullToRefresh'
 pod 'Mantle'
-pod 'DTCoreText', :head
+pod 'DTCoreText'
 pod 'HPGrowingTextView'
 pod 'GCPlaceholderTextView'
diff --git a/Podfile.lock b/Podfile.lock
index 7433dc7..1bffb37 100644
--- a/Podfile.lock
+++ b/Podfile.lock
@@ -1,55 +1,47 @@
-
 PODS:
-- DTCoreText (HEAD based on 1.3.2):
-  - DTFoundation/Core (~> 1.1)
-  - DTFoundation/DTHMLParser (~> 1.0)
-- DTFoundation/Core (1.1.0)
-- DTFoundation/DTHMLParser (1.1.0):
-  - DTFoundation/Core
-- GCPlaceholderTextView (1.0.1)
-- HPGrowingTextView (0.0.1)
-- MKNetworkKit (0.87):
-  - Reachability (~> 3.1.0)
-- Mantle (1.0):
-  - libextobjc/EXTKeyPathCoding
-  - libextobjc/EXTScope
-- Reachability (3.1.0)
-- SDWebImage (3.2):
-  - SDWebImage/MapKit (= 3.2)
-- SDWebImage/MapKit (3.2)
-- SVProgressHUD (0.8)
-- SVPullToRefresh (0.4.1)
-- libextobjc/EXTKeyPathCoding (0.2.5):
-  - libextobjc/RuntimeExtensions
-- libextobjc/EXTScope (0.2.5):
-  - libextobjc/RuntimeExtensions
-- libextobjc/RuntimeExtensions (0.2.5)
+  - DTCoreText (1.6.8):
+    - DTFoundation/Core (~> 1.5.4)
+    - DTFoundation/DTHTMLParser (~> 1.5.4)
+    - DTFoundation/UIKit (~> 1.5.4)
+  - DTFoundation/Core (1.5.4)
+  - DTFoundation/DTHTMLParser (1.5.4):
+    - DTFoundation/Core
+  - DTFoundation/UIKit (1.5.4):
+    - DTFoundation/Core
+  - GCPlaceholderTextView (1.0.1)
+  - HPGrowingTextView (1.0.1)
+  - Mantle (1.3.1):
+    - Mantle/extobjc
+  - Mantle/extobjc (1.3.1)
+  - MKNetworkKit (0.87):
+    - Reachability (~> 3.1.0)
+  - Reachability (3.1.1)
+  - SDWebImage (3.5):
+    - SDWebImage/Core
+  - SDWebImage/Core (3.5)
+  - SVProgressHUD (1.0)
+  - SVPullToRefresh (0.4.1)
 
 DEPENDENCIES:
-- DTCoreText (HEAD)
-- GCPlaceholderTextView
-- HPGrowingTextView
-- MKNetworkKit
-- Mantle
-- SDWebImage
-- SVProgressHUD
-- SVPullToRefresh
+  - DTCoreText
+  - GCPlaceholderTextView
+  - HPGrowingTextView
+  - Mantle
+  - MKNetworkKit
+  - SDWebImage
+  - SVProgressHUD
+  - SVPullToRefresh
 
 SPEC CHECKSUMS:
-  DTCoreText: ea0506fd102311311da09a3842170ce07f0a1b29
-  DTFoundation/Core: d84efdb26b073826cc526d3b00fcbb5b47ffe176
-  DTFoundation/DTHMLParser: d84efdb26b073826cc526d3b00fcbb5b47ffe176
+  DTCoreText: 24f96ab529f19114533ca71922469c94fb73db4d
+  DTFoundation: 86e59f373c7a9b9f859f8a9c1debf072979eebec
   GCPlaceholderTextView: 5eeef8d07a1dece8fdcd7762dfc21b8e89800838
-  HPGrowingTextView: 42fee2f684a8c98e61bc19579d274d7fc12b48ca
-  MKNetworkKit: 79a362de7fdcae82b714c45e0003c52b3b6e53c8
-  Mantle: aa9860e40cc365a094ef60fec46848fee7b03ca7
-  Reachability: ba94ecd4eaa037be3d0588b38956672588530c5b
-  SDWebImage: 8082fe8d658ccafaaecd9e5ecda12ed01f09ba9c
-  SDWebImage/MapKit: 8082fe8d658ccafaaecd9e5ecda12ed01f09ba9c
-  SVProgressHUD: 51042a14e3a716efdbdd73cbb2181fb23ee94389
+  HPGrowingTextView: fd77b93b9096dd1493a312c8856810b652b04dcc
+  Mantle: abc3b0c81bc66eb624cf9cebb8640e377d5a44ae
+  MKNetworkKit: f174100f92473012138b6b1c3040266af8d43a14
+  Reachability: 2be6bc2fd2bd31d97f5db33e75e4b29c79e95883
+  SDWebImage: f1a72472f8a2d54445f1fedafe2090593d9caf7f
+  SVProgressHUD: 5e10939a296debf5fe5a5895eda9539b8b2114f1
   SVPullToRefresh: 61a0e4bd12bd6f8e3465909810b0fbeb1a28d5f2
-  libextobjc/EXTKeyPathCoding: 2cbc74caf8bdc74a86fdf24673f773c83424ea98
-  libextobjc/EXTScope: 2cbc74caf8bdc74a86fdf24673f773c83424ea98
-  libextobjc/RuntimeExtensions: 2cbc74caf8bdc74a86fdf24673f773c83424ea98
 
-COCOAPODS: 0.16.4
+COCOAPODS: 0.27.1
diff --git a/RubyChina/Models/User.m b/RubyChina/Models/User.m
index 2e16b89..f070f20 100644
--- a/RubyChina/Models/User.m
+++ b/RubyChina/Models/User.m
@@ -28,6 +28,10 @@ +(User *) initWithDictionary:(NSDictionary *)obj{
     user.githubUrl = [obj objectForKey:@"github_url"];
     user.bio = [obj objectForKey:@"bio"];
     
+    if ([user.bio isKindOfClass:[NSNull class]]) {
+        user.bio = @"";
+    }
+    
     return user;
 }
 
diff --git a/RubyChina/UsersController.m b/RubyChina/UsersController.m
index d03b415..714b7a8 100644
--- a/RubyChina/UsersController.m
+++ b/RubyChina/UsersController.m
@@ -219,6 +219,7 @@ - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPa
     if (indexPath.section == 0) {        
         CGSize constraint = CGSizeMake(320 - 2 * 10, 20000.0f);
         
+        //当user.bio为<null>时，会出错
         CGSize size = [self.user.bio sizeWithFont:[UIFont systemFontOfSize:16.0] constrainedToSize:constraint lineBreakMode:UILineBreakModeWordWrap];
         height = size.height + 120.0f;
     }else{