diff --git a/Gemfile.lock b/Gemfile.lock
index f0278cef2c..9431c3636d 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -129,7 +129,7 @@ GEM
     factory_girl_rails (4.3.0)
       factory_girl (~> 4.3.0)
       railties (>= 3.0.0)
-    faraday (0.8.8)
+    faraday (0.8.9)
       multipart-post (~> 1.2.0)
     faraday_middleware (0.9.0)
       faraday (>= 0.7.4, < 0.9)
@@ -234,7 +234,7 @@ GEM
       activesupport (>= 4.0.1)
       haml (>= 3.1, < 5.0)
       railties (>= 4.0.1)
-    hashie (2.0.5)
+    hashie (2.1.2)
     hike (1.2.3)
     hipchat (0.14.0)
       httparty
@@ -243,7 +243,7 @@ GEM
     httparty (0.13.0)
       json (~> 1.8)
       multi_xml (>= 0.5.2)
-    httpauth (0.2.0)
+    httpauth (0.2.1)
     i18n (0.6.11)
     ice_nine (0.10.0)
     jasmine (2.0.2)
@@ -264,7 +264,7 @@ GEM
     jquery-ui-rails (4.2.1)
       railties (>= 3.2.16)
     json (1.8.1)
-    jwt (0.1.8)
+    jwt (0.1.13)
       multi_json (>= 1.5)
     kaminari (0.15.1)
       actionpack (>= 3.0.0)
@@ -311,9 +311,9 @@ GEM
     omniauth-github (1.1.1)
       omniauth (~> 1.0)
       omniauth-oauth2 (~> 1.1)
-    omniauth-google-oauth2 (0.2.1)
-      omniauth (~> 1.0)
-      omniauth-oauth2
+    omniauth-google-oauth2 (0.2.5)
+      omniauth (> 1.0)
+      omniauth-oauth2 (~> 1.1)
     omniauth-oauth (1.0.1)
       oauth
       omniauth (~> 1.0)
diff --git a/VERSION b/VERSION
index 5a47513a6e..d2bc4d2629 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-7.2.0.rc4-ee
+7.2.0.rc5-ee
diff --git a/app/models/concerns/issuable.rb b/app/models/concerns/issuable.rb
index 0a5fe24b5a..5c9b44812b 100644
--- a/app/models/concerns/issuable.rb
+++ b/app/models/concerns/issuable.rb
@@ -138,6 +138,10 @@ module Issuable
     labels.order('title ASC').pluck(:title)
   end
 
+  def remove_labels
+    labels.delete_all
+  end
+
   def add_labels_by_names(label_names)
     label_names.each do |label_name|
       label = project.labels.create_with(
diff --git a/app/models/label.rb b/app/models/label.rb
index 3ff52416c2..233f477444 100644
--- a/app/models/label.rb
+++ b/app/models/label.rb
@@ -6,14 +6,14 @@ class Label < ActiveRecord::Base
   has_many :issues, through: :label_links, source: :target, source_type: 'Issue'
 
   validates :color,
-            format: { with: /\A\#[0-9A-Fa-f]{6}+\Z/ },
+            format: { with: /\A#[0-9A-Fa-f]{6}\Z/ },
             allow_blank: false
   validates :project, presence: true
 
   # Don't allow '?', '&', and ',' for label titles
   validates :title,
             presence: true,
-            format: { with: /\A[^&\?,&]*\z/ },
+            format: { with: /\A[^&\?,&]+\z/ },
             uniqueness: { scope: :project_id }
 
   scope :order_by_name, -> { reorder("labels.title ASC") }
diff --git a/doc/integration/google.md b/doc/integration/google.md
index 3cf546bd77..7a78aff8ea 100644
--- a/doc/integration/google.md
+++ b/doc/integration/google.md
@@ -2,17 +2,21 @@
 
 To enable the Google OAuth2 OmniAuth provider you must register your application with Google. Google will generate a client ID and secret key for you to use.
 
-1.  Sign in to the [Google Developers Console](https://console.developers.google.com/) with the Google account you want to use to register GitLab. 
+1.  Sign in to the [Google Developers Console](https://console.developers.google.com/) with the Google account you want to use to register GitLab.
 
 1.  Select "Create Project".
 
 1.  Provide the project information
-    - Project name: 'GitLab' works just fine here. 
+    - Project name: 'GitLab' works just fine here.
     - Project ID: Must be unique to all Google Developer registered applications. Google provides a randomly generated Project ID by default. You can use the randomly generated ID or choose a new one.
 1. Refresh the page. You should now see your new project in the list. Click on the project.
 
 1. Select "APIs & auth" in the left menu.
 
+1. Select "APIs" in the submenu.
+    - Enable `Contacts API`
+    - Enable `Google+ API`
+
 1. Select "Credentials" in the submenu.
 
 1. Select "Create New Client ID".
@@ -41,7 +45,7 @@ To enable the Google OAuth2 OmniAuth provider you must register your application
              args: { access_type: 'offline', approval_prompt: '' } }
     ```
 
-1.  Change 'YOUR APP ID' to the client ID from the GitHub application page from step 7. 
+1.  Change 'YOUR APP ID' to the client ID from the GitHub application page from step 7.
 
 1.  Change 'YOUR APP SECRET' to the client secret from the GitHub application page  from step 7.
 
@@ -51,12 +55,12 @@ To enable the Google OAuth2 OmniAuth provider you must register your application
 
 On the sign in page there should now be a Google icon below the regular sign in form. Click the icon to begin the authentication process. Google will ask the user to sign in and authorize the GitLab application. If everything goes well the user will be returned to GitLab and will be signed in.
 
-## Further Configuration 
+## Further Configuration
 
 This further configuration is not required for Google authentication to function but it is strongly recommended. Taking these steps will increase usability for users by providing a little more recognition and branding.
 
 At this point, when users first try to authenticate to your GitLab installation with Google they will see a generic application name on the prompt screen. The prompt informs the user that "Project Default Service Account" would like to access their account. "Project Default Service Account" isn't very recognizable and may confuse or cause users to be concerned. This is easily changeable.
 
 1. Select 'Consent screen' in the left menu. (See steps 1, 4 and 5 above for instructions on how to get here if you closed your window).
-1. Scroll down until you find "Product Name". Change the product name to something more descriptive. 
+1. Scroll down until you find "Product Name". Change the product name to something more descriptive.
 1. Add any additional information as you wish - homepage, logo, privacy policy, etc. None of this is required, but it may help your users.
diff --git a/doc/update/6.0-to-7.2.md b/doc/update/6.0-to-7.2.md
index 41ff628360..913768aee0 100644
--- a/doc/update/6.0-to-7.2.md
+++ b/doc/update/6.0-to-7.2.md
@@ -84,7 +84,7 @@ sudo chmod u+rwx,g+rx,o-rwx /home/git/gitlab-satellites
 
 ## 6. Update config files
 
-TIP: to see what changed in gitlab.yml.example in this release use next command: 
+TIP: to see what changed in gitlab.yml.example in this release use next command:
 
 ```
 git diff 6-0-stable:config/gitlab.yml.example 7-2-stable:config/gitlab.yml.example
@@ -129,6 +129,12 @@ To make sure you didn't miss anything run a more thorough check with:
 
 If all items are green, then congratulations upgrade complete!
 
+## 10. Update OmniAuth configuration
+
+When using Google omniauth login, changes of the Google account required.
+Ensure that `Contacts API` and the `Google+ API` are enabled in the [Google Developers Console](https://console.developers.google.com/).
+More details can be found at the [integration documentation](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/integration/google.md).
+
 ## Things went south? Revert to previous version (6.0)
 
 ### 1. Revert the code to the previous version
@@ -144,4 +150,4 @@ sudo -u git -H bundle exec rake gitlab:backup:restore RAILS_ENV=production
 
 ## Login issues after upgrade?
 
-If running in HTTPS mode, be sure to read [Can't Verify CSRF token authenticity](https://github.com/gitlabhq/gitlab-public-wiki/wiki/Trouble-Shooting-Guide#cant-verify-csrf-token-authenticitycant-get-past-login-pageredirected-to-login-page) 
+If running in HTTPS mode, be sure to read [Can't Verify CSRF token authenticity](https://github.com/gitlabhq/gitlab-public-wiki/wiki/Trouble-Shooting-Guide#cant-verify-csrf-token-authenticitycant-get-past-login-pageredirected-to-login-page)
diff --git a/doc/update/7.1-to-7.2.md b/doc/update/7.1-to-7.2.md
index be28944a8f..40698e8092 100644
--- a/doc/update/7.1-to-7.2.md
+++ b/doc/update/7.1-to-7.2.md
@@ -91,6 +91,12 @@ To make sure you didn't miss anything run a more thorough check with:
 
 If all items are green, then congratulations upgrade is complete!
 
+### 8. Update OmniAuth configuration
+
+When using Google omniauth login, changes of the Google account required.
+Ensure that `Contacts API` and the `Google+ API` are enabled in the [Google Developers Console](https://console.developers.google.com/).
+More details can be found at the [integration documentation](../integration/google.md).
+
 ## Things went south? Revert to previous version (7.1)
 
 ### 1. Revert the code to the previous version
diff --git a/lib/api/helpers.rb b/lib/api/helpers.rb
index d36b29a00b..6af0f6d1b2 100644
--- a/lib/api/helpers.rb
+++ b/lib/api/helpers.rb
@@ -114,17 +114,21 @@ module API
 
     # Helper method for validating all labels against its names
     def validate_label_params(params)
+      errors = {}
+
       if params[:labels].present?
         params[:labels].split(',').each do |label_name|
           label = user_project.labels.create_with(
             color: Label::DEFAULT_COLOR).find_or_initialize_by(
               title: label_name.strip)
+
           if label.invalid?
-            return true
+            errors[label.title] = label.errors
           end
         end
       end
-      false
+
+      errors
     end
 
     # error helpers
diff --git a/lib/api/issues.rb b/lib/api/issues.rb
index 055529ccbd..eb6a74cd2b 100644
--- a/lib/api/issues.rb
+++ b/lib/api/issues.rb
@@ -52,8 +52,8 @@ module API
         attrs = attributes_for_keys [:title, :description, :assignee_id, :milestone_id]
 
         # Validate label names in advance
-        if validate_label_params(params)
-          return render_api_error!('Label names invalid', 405)
+        if (errors = validate_label_params(params)).any?
+          render_api_error!({ labels: errors }, 400)
         end
 
         issue = ::Issues::CreateService.new(user_project, current_user, attrs).execute
@@ -90,8 +90,8 @@ module API
         attrs = attributes_for_keys [:title, :description, :assignee_id, :milestone_id, :state_event]
 
         # Validate label names in advance
-        if validate_label_params(params)
-          return render_api_error!('Label names invalid', 405)
+        if (errors = validate_label_params(params)).any?
+          render_api_error!({ labels: errors }, 400)
         end
 
         issue = ::Issues::UpdateService.new(user_project, current_user, attrs).execute(issue)
@@ -99,7 +99,8 @@ module API
         if issue.valid?
           # Find or create labels and attach to issue. Labels are valid because
           # we already checked its name, so there can't be an error here
-          if params[:labels].present?
+          unless params[:labels].nil?
+            issue.remove_labels
             # Create and add labels to the new created issue
             issue.add_labels_by_names(params[:labels].split(','))
           end
diff --git a/spec/models/label_spec.rb b/spec/models/label_spec.rb
index 5098af84cc..1d273e59bd 100644
--- a/spec/models/label_spec.rb
+++ b/spec/models/label_spec.rb
@@ -5,4 +5,27 @@ describe Label do
   it { label.should be_valid }
 
   it { should belong_to(:project) }
+
+  describe 'Validation' do
+    it 'should validate color code' do
+      build(:label, color: 'G-ITLAB').should_not be_valid
+      build(:label, color: 'AABBCC').should_not be_valid
+      build(:label, color: '#AABBCCEE').should_not be_valid
+      build(:label, color: '#GGHHII').should_not be_valid
+      build(:label, color: '#').should_not be_valid
+      build(:label, color: '').should_not be_valid
+
+      build(:label, color: '#AABBCC').should be_valid
+    end
+
+    it 'should validate title' do
+      build(:label, title: 'G,ITLAB').should_not be_valid
+      build(:label, title: 'G?ITLAB').should_not be_valid
+      build(:label, title: 'G&ITLAB').should_not be_valid
+      build(:label, title: '').should_not be_valid
+
+      build(:label, title: 'GITLAB').should be_valid
+      build(:label, title: 'gitlab').should be_valid
+    end
+  end
 end
diff --git a/spec/requests/api/issues_spec.rb b/spec/requests/api/issues_spec.rb
index d8e8e4f503..08dc94ebdf 100644
--- a/spec/requests/api/issues_spec.rb
+++ b/spec/requests/api/issues_spec.rb
@@ -73,12 +73,12 @@ describe API::API, api: true  do
       response.status.should == 400
     end
 
-    it 'should return 405 on invalid label names' do
+    it 'should return 400 on invalid label names' do
       post api("/projects/#{project.id}/issues", user),
            title: 'new issue',
            labels: 'label, ?'
-      response.status.should == 405
-      json_response['message'].should == 'Label names invalid'
+      response.status.should == 400
+      json_response['message']['labels']['?']['title'].should == ['is invalid']
     end
   end
 
@@ -97,12 +97,56 @@ describe API::API, api: true  do
       response.status.should == 404
     end
 
-    it 'should return 405 on invalid label names' do
+    it 'should return 400 on invalid label names' do
       put api("/projects/#{project.id}/issues/#{issue.id}", user),
           title: 'updated title',
           labels: 'label, ?'
-      response.status.should == 405
-      json_response['message'].should == 'Label names invalid'
+      response.status.should == 400
+      json_response['message']['labels']['?']['title'].should == ['is invalid']
+    end
+  end
+
+  describe 'PUT /projects/:id/issues/:issue_id to update labels' do
+    let!(:label) { create(:label, title: 'dummy', project: project) }
+    let!(:label_link) { create(:label_link, label: label, target: issue) }
+
+    it 'should not update labels if not present' do
+      put api("/projects/#{project.id}/issues/#{issue.id}", user),
+          title: 'updated title'
+      response.status.should == 200
+      json_response['labels'].should == [label.title]
+    end
+
+    it 'should remove all labels' do
+      put api("/projects/#{project.id}/issues/#{issue.id}", user),
+          labels: ''
+      response.status.should == 200
+      json_response['labels'].should == []
+    end
+
+    it 'should update labels' do
+      put api("/projects/#{project.id}/issues/#{issue.id}", user),
+          labels: 'foo,bar'
+      response.status.should == 200
+      json_response['labels'].should include 'foo'
+      json_response['labels'].should include 'bar'
+    end
+
+    it 'should return 400 on invalid label names' do
+      put api("/projects/#{project.id}/issues/#{issue.id}", user),
+          labels: 'label, ?'
+      response.status.should == 400
+      json_response['message']['labels']['?']['title'].should == ['is invalid']
+    end
+
+    it 'should allow special label names' do
+      put api("/projects/#{project.id}/issues/#{issue.id}", user),
+          labels: 'label:foo, label-bar,label_bar,label/bar'
+      response.status.should == 200
+      json_response['labels'].should include 'label:foo'
+      json_response['labels'].should include 'label-bar'
+      json_response['labels'].should include 'label_bar'
+      json_response['labels'].should include 'label/bar'
     end
   end
 
diff --git a/spec/requests/api/labels_spec.rb b/spec/requests/api/labels_spec.rb
index cd1b84c53c..ee9088933a 100644
--- a/spec/requests/api/labels_spec.rb
+++ b/spec/requests/api/labels_spec.rb
@@ -50,6 +50,14 @@ describe API::API, api: true  do
       json_response['message'].should == 'Color is invalid'
     end
 
+    it 'should return 400 for too long color code' do
+      post api("/projects/#{project.id}/labels", user),
+           name: 'Foo',
+           color: '#FFAAFFFF'
+      response.status.should == 400
+      json_response['message'].should == 'Color is invalid'
+    end
+
     it 'should return 400 for invalid name' do
       post api("/projects/#{project.id}/labels", user),
            name: '?',
@@ -147,5 +155,13 @@ describe API::API, api: true  do
       response.status.should == 400
       json_response['message'].should == 'Color is invalid'
     end
+
+    it 'should return 400 for too long color code' do
+      post api("/projects/#{project.id}/labels", user),
+           name: 'Foo',
+           color: '#FFAAFFFF'
+      response.status.should == 400
+      json_response['message'].should == 'Color is invalid'
+    end
   end
 end