diff --git a/fluent-plugin-couch.gemspec b/fluent-plugin-couch.gemspec
index 018272c..1119f8d 100755
--- a/fluent-plugin-couch.gemspec
+++ b/fluent-plugin-couch.gemspec
@@ -9,7 +9,7 @@ Gem::Specification.new do |s|
 
   s.required_rubygems_version = Gem::Requirement.new(">= 0") if s.respond_to? :required_rubygems_version=
   s.authors = ["Yuri Odagiri"]
-  s.date = "2014-01-29"
+  s.date = "2015-07-02"
   s.email = "ixixizko@gmail.com"
   s.extra_rdoc_files = [
     "README.rdoc"
@@ -22,11 +22,11 @@ Gem::Specification.new do |s|
   ]
   s.homepage = "http://github.com/ixixi/fluent-plugin-couch"
   s.require_paths = ["lib"]
-  s.rubygems_version = "1.8.23"
+  s.rubygems_version = "2.0.14"
   s.summary = "CouchDB output plugin for Fluentd event collector"
 
   if s.respond_to? :specification_version then
-    s.specification_version = 3
+    s.specification_version = 4
 
     if Gem::Version.new(Gem::VERSION) >= Gem::Version.new('1.2.0') then
       s.add_runtime_dependency(%q<fluentd>, ["~> 0.10.0"])