diff --git a/lib/logstash/outputs/slack.rb b/lib/logstash/outputs/slack.rb
index 047f404..dfca9d8 100644
--- a/lib/logstash/outputs/slack.rb
+++ b/lib/logstash/outputs/slack.rb
@@ -36,6 +36,24 @@ def register
     @content_type = "application/x-www-form-urlencoded"
   end # def register
 
+  private
+  def recursive_sprintf(event, node)
+    case node
+      when String
+        ret = event.sprintf(node)
+      when Array
+        ret = node.map do |obj|
+          recursive_sprintf( event, obj )
+        end
+      when Hash
+        ret = Hash.new
+        node.each_pair do |key, value|
+          ret[key] = recursive_sprintf( event, value )
+        end
+     end
+     ret
+  end
+
   public
   def receive(event)
     return unless output?(event)
@@ -61,7 +79,7 @@ def receive(event)
     end
 
     if @attachments and @attachments.any?
-      payload_json['attachments'] = @attachments.map { |x| JSON.parse(event.sprintf(JSON.dump(x))) }
+      payload_json['attachments'] = recursive_sprintf(event , @attachments)
     end
     if event.include?('attachments') and event.get('attachments').is_a?(Array)
       if event.get('attachments').any?
diff --git a/logstash-output-slack.gemspec b/logstash-output-slack.gemspec
index 1e62382..222a588 100644
--- a/logstash-output-slack.gemspec
+++ b/logstash-output-slack.gemspec
@@ -1,6 +1,6 @@
 Gem::Specification.new do |s|
   s.name            = 'logstash-output-slack'
-  s.version         = '2.1.1'
+  s.version         = '7.0.0'
   s.licenses        = ['MIT','Apache License (2.0)']
   s.summary         = "Write events to Slack"
   s.description     = "This gem is a logstash plugin required to be installed on top of the Logstash core pipeline using $LS_HOME/bin/plugin install gemname. This gem is not a stand-alone program"
@@ -21,7 +21,7 @@ Gem::Specification.new do |s|
   # Gem dependencies
 
   s.add_runtime_dependency "logstash-core-plugin-api", ">= 1.60", "<= 2.99"
-  s.add_runtime_dependency "public_suffix", "< 1.5.0"
+  s.add_runtime_dependency "public_suffix"
   
   s.add_runtime_dependency "logstash-codec-plain"
   s.add_runtime_dependency "rest-client", '~> 1.8', ">= 1.8.0"
diff --git a/spec/outputs/slack_spec.rb b/spec/outputs/slack_spec.rb
index fe1cbad..f90fb35 100644
--- a/spec/outputs/slack_spec.rb
+++ b/spec/outputs/slack_spec.rb
@@ -228,6 +228,35 @@ def test_one_event(event, expected_json, expected_url = "http://requestb.in/r9lk
         test_one_event(event, expected_json)
       end
     end
+
+    context "when attachements contain interpolations" do
+      let(:data) { {
+        "message" => "This message should show in slack",
+        "x" => "3",
+        "image" => "http://example.com/image.png",
+        "textquot" => "Text with \"quotation marks\"",
+      } }
+
+      let(:config) { {
+        "url" => "http://requestb.in/r9lkbzr9",
+        "attachments" => [
+          {"image_url" => "%{image}",
+          "textquot" => "%{textquot}"
+          }
+        ]
+      } }
+
+      it "uses and formats all provided values" do
+        expected_json = {
+          :text => "This message should show in slack",
+          :attachments => [{
+            :image_url => "http://example.com/image.png",
+            :textquot => "Text with \"quotation marks\""
+          }]
+        }
+        test_one_event(event, expected_json)
+      end
+    end
   end
 
   describe "interpolation in url field" do