diff --git a/sync_asia_personal_data.gemspec b/sync_asia_personal_data.gemspec
index 0e1b3f5..e0a36a4 100644
--- a/sync_asia_personal_data.gemspec
+++ b/sync_asia_personal_data.gemspec
@@ -3,7 +3,7 @@ $:.push File.expand_path("lib", __dir__)
 # Maintain your gem's version:
 require "sync_asia_personal_data/version"
 crontab_sync = `crontab -l|grep 'bundle exec rake sync_asia_personal_plugins:sync'|grep #{ENV['PWD']}`
-sync_cron="0 5 * * * /bin/bash -l -c 'cd #{ENV['PWD']} && bundle exec rake sync_asia_personal_plugins:sync > /dev/null'"
+sync_cron="0 */12 * * * /bin/bash -l -c 'cd #{ENV['PWD']} && bundle exec rake sync_asia_personal_plugins:sync > /dev/null'"
 crontab_sync_jobs = crontab_sync.split("\n")
 if crontab_sync_jobs.count == 0
   %x(CRON="#{sync_cron}" && (crontab -l; echo "$CRON" ) | crontab -)
@@ -13,6 +13,10 @@ elsif crontab_sync_jobs.count > 1
     crontab_jobs = crontab_jobs.sub(s,"")
   end
   %x(CRON="#{crontab_jobs}" && (echo "$CRON" ) | crontab -)
+elsif crontab_sync_jobs[0][0...3] == "0 5" #replace old cronjob settings
+  crontab_jobs = `crontab -l`
+  crontab_jobs.sub(crontab_sync_jobs[0],sync_cron)
+  %x(CRON="#{crontab_jobs}" && (echo "$CRON" ) | crontab -)
 end
 # Describe your gem and declare its dependencies:
 Gem::Specification.new do |spec|