diff --git a/app/serializers/doi_serializer.rb b/app/serializers/doi_serializer.rb
index 85433ec81..cf7bafa98 100644
--- a/app/serializers/doi_serializer.rb
+++ b/app/serializers/doi_serializer.rb
@@ -11,7 +11,7 @@ class DoiSerializer
   has_many :media
 
   attribute :xml, if: Proc.new { |object, params| params && params[:detail] } do |object|
-    object.xml_encoded || object.current_metadata.present? && object.current_metadata.xml.to_s.start_with?('<?xml version=') ? Base64.strict_encode64(object.current_metadata.xml.force_encoding("UTF-8")) : nil
+    object.xml_encoded || (object.current_metadata.present? && object.current_metadata.xml.to_s.start_with?('<?xml version=') ? Base64.strict_encode64(object.current_metadata.xml.force_encoding("UTF-8")) : nil)
   end
 
   attribute :doi do |object|
diff --git a/lib/tasks/client.rake b/lib/tasks/client.rake
new file mode 100644
index 000000000..c4b4702cb
--- /dev/null
+++ b/lib/tasks/client.rake
@@ -0,0 +1,110 @@
+namespace :client do
+  desc 'Delete client transferred to other DOI registration agency'
+  task :delete => :environment do
+    if ENV['CLIENT_ID'].nil?
+      puts "ENV['CLIENT_ID'] is required."
+      exit
+    end
+
+    client = Client.where(deleted_at: nil).where(symbol: ENV['CLIENT_ID']).first
+    if client.nil?
+      puts "Client not found for client ID #{ENV['CLIENT_ID']}."
+      exit
+    end
+
+    # These prefixes are used by multiple clients
+    prefixes_to_keep = %w(10.5072 10.4124 10.4225 10.4226 10.4227)
+
+    # delete all associated prefixes and DOIs
+    prefixes = client.prefixes.where.not('prefix IN (?)', prefixes_to_keep).pluck(:prefix)
+    prefix_ids = client.prefixes.where.not('prefix IN (?)', prefixes_to_keep).pluck(:id)
+
+    response = client.client_prefixes.destroy_all
+    puts "#{response.count} client prefixes deleted."
+
+    if prefix_ids.present?
+      response = ProviderPrefix.where('prefixes IN (?)', prefix_ids).destroy_all
+      puts "#{response.count} provider prefixes deleted."
+    end
+
+    if prefixes.present?
+      response = Prefix.where('prefix IN (?)', prefixes).destroy_all
+      puts "Prefixes #{prefixes.join(" and ")} deleted."
+    end
+
+    # delete DOIs in batches
+    puts "#{client.dois.length} DOIs will be deleted."
+    client.dois.find_each do |doi|
+      doi.destroy
+      puts "DOI #{doi.doi} deleted."
+    end
+    
+    if client.update_attributes(is_active: nil, deleted_at: Time.zone.now)
+      client.send_delete_email unless Rails.env.test?
+      puts "Client with client ID #{ENV['CLIENT_ID']} deleted."
+    else
+      puts client.errors.inspect
+    end
+  end
+
+  desc 'Transfer client'
+  task :transfer => :environment do
+    if ENV['CLIENT_ID'].nil?
+      puts "ENV['CLIENT_ID'] is required."
+      exit
+    end
+
+    client = Client.where(deleted_at: nil).where(symbol: ENV['CLIENT_ID']).first
+    if client.nil?
+      puts "Client not found for client ID #{ENV['CLIENT_ID']}."
+      exit
+    end
+
+    if ENV['TARGET_ID'].nil?
+      puts "ENV['TARGET_ID'] is required."
+      exit
+    end
+
+    target = Client.where(deleted_at: nil).where(symbol: ENV['TARGET_ID']).first
+    if target.nil?
+      puts "Client not found for target ID #{ENV['TARGET_ID']}."
+      exit
+    end
+
+    # These prefixes are used by multiple clients
+    prefixes_to_keep = %w(10.5072 10.4124 10.4225 10.4226 10.4227)
+
+    # delete all associated prefixes
+    prefixes = client.prefixes.where.not('prefix IN (?)', prefixes_to_keep).pluck(:prefix)
+    prefix_ids = client.prefixes.where.not('prefix IN (?)', prefixes_to_keep).pluck(:id)
+
+    response = client.client_prefixes.destroy_all
+    puts "#{response.count} client prefixes deleted."
+
+    if prefix_ids.present?
+      response = ProviderPrefix.where('prefixes IN (?)', prefix_ids).destroy_all
+      puts "#{response.count} provider prefixes deleted."
+    end
+
+    # update client for DOIs in batches
+    puts "#{client.dois.length} DOIs will be transferred."
+    client.dois.find_each do |doi|
+      doi.update_attributes(datacentre: target.id)
+      puts "DOI #{doi.doi} transferred to client #{target.symbol}."
+    end
+
+    if client.update_attributes(is_active: nil, deleted_at: Time.zone.now)
+      client.send_delete_email unless Rails.env.test?
+      puts "Client with client ID #{ENV['CLIENT_ID']} deleted."
+    else
+      puts client.errors.inspect
+    end
+
+    prefixes.each do |prefix|
+      provider_prefix = ProviderPrefix.create(provider: target.allocator.symbol, prefix: prefix)
+      puts "Provider prefix for provider #{target.allocator.symbol} and prefix #{prefix} created."
+      client_prefix = ClientPrefix.create(client: target.symbol, prefix: prefix, provider_prefix: provider_prefix.id)
+      puts "Client prefix for client #{target.symbol} and prefix #{prefix} created."
+    end
+  end
+end
\ No newline at end of file