diff --git a/github_changelog_generator.gemspec b/github_changelog_generator.gemspec
index f704d8bf5..0fe545df7 100644
--- a/github_changelog_generator.gemspec
+++ b/github_changelog_generator.gemspec
@@ -24,7 +24,6 @@ Gem::Specification.new do |spec|
   spec.require_paths = ["lib"]
 
   spec.add_runtime_dependency("activesupport")
-  spec.add_runtime_dependency("async", ">= 1.25.0")
   spec.add_runtime_dependency("async-http-faraday")
   spec.add_runtime_dependency("faraday-http-cache")
   spec.add_runtime_dependency("multi_json")
diff --git a/lib/github_changelog_generator/generator/generator.rb b/lib/github_changelog_generator/generator/generator.rb
index 143d60e85..a076348e8 100644
--- a/lib/github_changelog_generator/generator/generator.rb
+++ b/lib/github_changelog_generator/generator/generator.rb
@@ -49,21 +49,18 @@ def initialize(options = {})
     # @return [String] Generated changelog file
     def compound_changelog
       @options.load_custom_ruby_files
-
-      Sync do
-        fetch_and_filter_tags
-        fetch_issues_and_pr
-
-        log = if @options[:unreleased_only]
-                generate_entry_between_tags(@filtered_tags[0], nil)
-              else
-                generate_entries_for_all_tags
-              end
-        log += File.read(@options[:base]) if File.file?(@options[:base])
-        log = remove_old_fixed_string(log)
-        log = insert_fixed_string(log)
-        @log = log
-      end
+      fetch_and_filter_tags
+      fetch_issues_and_pr
+
+      log = if @options[:unreleased_only]
+              generate_entry_between_tags(@filtered_tags[0], nil)
+            else
+              generate_entries_for_all_tags
+            end
+      log += File.read(@options[:base]) if File.file?(@options[:base])
+      log = remove_old_fixed_string(log)
+      log = insert_fixed_string(log)
+      @log = log
     end
 
     private
diff --git a/lib/github_changelog_generator/octo_fetcher.rb b/lib/github_changelog_generator/octo_fetcher.rb
index fb36b6aa4..34d521d06 100644
--- a/lib/github_changelog_generator/octo_fetcher.rb
+++ b/lib/github_changelog_generator/octo_fetcher.rb
@@ -227,6 +227,8 @@ def fetch_events_async(issues)
 
         # to clear line from prev print
         print_empty_line
+
+        client.agent.close
       end
 
       Helper.log.info "Fetching events for issues and PR: #{i}"
@@ -254,6 +256,8 @@ def fetch_comments_async(prs)
         end
 
         barrier.wait
+
+        client.agent.close
       end
 
       nil
@@ -313,6 +317,7 @@ def commits
           end
 
           barrier.wait
+          client.agent.close
 
           @commits.sort! do |b, a|
             a[:commit][:author][:date] <=> b[:commit][:author][:date]