diff --git a/README.md b/README.md
index b9f132a..992d89d 100644
--- a/README.md
+++ b/README.md
@@ -99,5 +99,5 @@ bin/logstash -f path-to-configuration-file -l /var/log/monasca/log/agent/test-lo
 
 ## Open tasks
 * Language translations (Replace hardcoded String messages with a configuration/language file)
-* Exception handling
+* Exception handling (monasca-api requests)
 * Contribute to logstash [http://www.elastic.co/guide/en/logstash/master/_how_to_write_a_logstash_output_plugin.html#_contributing_your_source_code_to_ulink_url_https_github_com_logstash_plugins_logstash_plugins_ulink_4]
\ No newline at end of file
diff --git a/logstash-output-monasca_api.gemspec b/logstash-output-monasca_api.gemspec
index 1f76a0b..c8088b8 100644
--- a/logstash-output-monasca_api.gemspec
+++ b/logstash-output-monasca_api.gemspec
@@ -18,8 +18,8 @@ Gem::Specification.new do |s|
   s.metadata = { 'logstash_plugin' => 'true', 'logstash_group' => 'output' }
 
   # Gem dependencies
-  s.add_runtime_dependency 'logstash-core', '>= 1.4.0', '< 2.0.0'
-  s.add_runtime_dependency 'logstash-codec-plain'
-  s.add_runtime_dependency 'rest-client'
-  s.add_development_dependency 'logstash-devutils'
+  s.add_runtime_dependency 'logstash-core', '~> 1.5.0'
+  s.add_runtime_dependency 'logstash-codec-plain', '~> 0.1.6'
+  s.add_runtime_dependency 'rest-client', '~> 1.8.0'
+  s.add_development_dependency 'logstash-devutils', '~> 0.0.14'
 end