diff --git a/Gemfile b/Gemfile
index 7f90ab5aa..088e25eea 100644
--- a/Gemfile
+++ b/Gemfile
@@ -108,7 +108,7 @@ group :production, :test do
 end
 
 group :test do
-  gem 'capybara', '~> 3.14'
+  gem 'capybara', '~> 3.15'
   gem 'climate_control', '~> 0.2'
   gem 'faker', '~> 1.9'
   gem 'microformats', '~> 4.1'
diff --git a/Gemfile.lock b/Gemfile.lock
index 5df1dc0ad..572a454ea 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -127,7 +127,7 @@ GEM
       sshkit (~> 1.3)
     capistrano-yarn (2.0.2)
       capistrano (~> 3.0)
-    capybara (3.14.0)
+    capybara (3.15.0)
       addressable
       mini_mime (>= 0.1.3)
       nokogiri (~> 1.8)
@@ -366,7 +366,7 @@ GEM
       concurrent-ruby (~> 1.0, >= 1.0.2)
       sidekiq (>= 3.5)
       statsd-ruby (~> 1.4, >= 1.4.0)
-    oj (3.7.10)
+    oj (3.7.11)
     omniauth (1.9.0)
       hashie (>= 3.4.6, < 3.7.0)
       rack (>= 1.6.2, < 3)
@@ -422,7 +422,7 @@ GEM
       pry (>= 0.10.4)
     psych (3.1.0)
     public_suffix (3.0.3)
-    puma (3.12.0)
+    puma (3.12.1)
     pundit (2.0.1)
       activesupport (>= 3.0.0)
     raabro (1.1.6)
@@ -672,7 +672,7 @@ DEPENDENCIES
   capistrano-rails (~> 1.4)
   capistrano-rbenv (~> 2.1)
   capistrano-yarn (~> 2.0)
-  capybara (~> 3.14)
+  capybara (~> 3.15)
   charlock_holmes (~> 0.7.6)
   chewy (~> 5.0)
   cld3 (~> 3.2.3)
diff --git a/app/controllers/concerns/account_controller_concern.rb b/app/controllers/concerns/account_controller_concern.rb
index 8817fd7de..4f28941ae 100644
--- a/app/controllers/concerns/account_controller_concern.rb
+++ b/app/controllers/concerns/account_controller_concern.rb
@@ -69,6 +69,10 @@ module AccountControllerConcern
   end
 
   def check_account_suspension
-    gone if @account.suspended?
+    if @account.suspended?
+      skip_session!
+      expires_in(3.minutes, public: true)
+      gone
+    end
   end
 end
diff --git a/app/lib/proof_provider/keybase/config_serializer.rb b/app/lib/proof_provider/keybase/config_serializer.rb
index 474ea74e2..557bafe84 100644
--- a/app/lib/proof_provider/keybase/config_serializer.rb
+++ b/app/lib/proof_provider/keybase/config_serializer.rb
@@ -2,6 +2,7 @@
 
 class ProofProvider::Keybase::ConfigSerializer < ActiveModel::Serializer
   include RoutingHelper
+  include ActionView::Helpers::TextHelper
 
   attributes :version, :domain, :display_name, :username,
              :brand_color, :logo, :description, :prefill_url,
@@ -29,11 +30,11 @@ class ProofProvider::Keybase::ConfigSerializer < ActiveModel::Serializer
   end
 
   def description
-    Setting.site_short_description.presence || Setting.site_description.presence || I18n.t('about.about_mastodon_html')
+    strip_tags(Setting.site_short_description.presence || I18n.t('about.about_mastodon_html'))
   end
 
   def username
-    { min: 1, max: 30, re: Account::USERNAME_RE.inspect }
+    { min: 1, max: 30, re: '[a-z0-9_]+([a-z0-9_\.-]+[a-z0-9_]+)?' }
   end
 
   def prefill_url
diff --git a/app/serializers/manifest_serializer.rb b/app/serializers/manifest_serializer.rb
index cc8b9a4d4..28127437d 100644
--- a/app/serializers/manifest_serializer.rb
+++ b/app/serializers/manifest_serializer.rb
@@ -18,7 +18,7 @@ class ManifestSerializer < ActiveModel::Serializer
   end
 
   def description
-    strip_tags(object.site_description.presence || I18n.t('about.about_mastodon_html'))
+    strip_tags(object.site_short_description.presence || I18n.t('about.about_mastodon_html'))
   end
 
   def icons
diff --git a/app/services/activitypub/fetch_remote_poll_service.rb b/app/services/activitypub/fetch_remote_poll_service.rb
index 44a23712c..854a32d05 100644
--- a/app/services/activitypub/fetch_remote_poll_service.rb
+++ b/app/services/activitypub/fetch_remote_poll_service.rb
@@ -5,6 +5,7 @@ class ActivityPub::FetchRemotePollService < BaseService
 
   def call(poll, on_behalf_of = nil)
     json = fetch_resource(poll.status.uri, true, on_behalf_of)
+    return unless supported_context?(json)
     ActivityPub::ProcessPollService.new.call(poll, json)
   end
 end
diff --git a/app/services/activitypub/process_poll_service.rb b/app/services/activitypub/process_poll_service.rb
index ee248169d..61357abd3 100644
--- a/app/services/activitypub/process_poll_service.rb
+++ b/app/services/activitypub/process_poll_service.rb
@@ -5,7 +5,7 @@ class ActivityPub::ProcessPollService < BaseService
 
   def call(poll, json)
     @json = json
-    return unless supported_context? && expected_type?
+    return unless expected_type?
 
     previous_expires_at = poll.expires_at
 
@@ -54,10 +54,6 @@ class ActivityPub::ProcessPollService < BaseService
 
   private
 
-  def supported_context?
-    super(@json)
-  end
-
   def expected_type?
     equals_or_includes_any?(@json['type'], %w(Question))
   end
diff --git a/config/initializers/omniauth.rb b/config/initializers/omniauth.rb
index 254e751d4..e8d7697a1 100644
--- a/config/initializers/omniauth.rb
+++ b/config/initializers/omniauth.rb
@@ -14,7 +14,7 @@ Devise.setup do |config|
     cas_options[:host] = ENV['CAS_HOST'] if ENV['CAS_HOST']
     cas_options[:port] = ENV['CAS_PORT'] if ENV['CAS_PORT']
     cas_options[:ssl] = ENV['CAS_SSL'] == 'true' if ENV['CAS_SSL']
-    cas_options[:validate_url] = ENV['CAS_VALIDATE_URL'] if ENV['CAS_VALIDATE_URL']
+    cas_options[:service_validate_url] = ENV['CAS_VALIDATE_URL'] if ENV['CAS_VALIDATE_URL']
     cas_options[:callback_url] = ENV['CAS_CALLBACK_URL'] if ENV['CAS_CALLBACK_URL']
     cas_options[:logout_url] = ENV['CAS_LOGOUT_URL'] if ENV['CAS_LOGOUT_URL']
     cas_options[:login_url] = ENV['CAS_LOGIN_URL'] if ENV['CAS_LOGIN_URL']