as per the document https://wiki.jenkins.io/display/JENKINS/Discard+Old+Build+plugin my jenkins has this plugin and defined days to keep buils as 60 but I observe there are old builds more than 60 days are available in the history.
what is the best way to to manage the old build? I am using Jenkins version 1.642.4.
The question of cleaning builds has been answered extensively in various forms:
https://superuser.com/questions/589528/how-do-i-delete-the-builds-11-to-1717-in-jenkins
How to remove old builds in jenkins?
Jenkins delete builds older than latest 20 builds for all jobs
How do I clear my Jenkins/Hudson build history?
As suggested in the last response, merely adding the plugin is not enough. You most likely need a system restart or possibly a new run of the job itself: that should clean up the history. Thst is for the built-in capability. You have referenced a post-build task step, which means the job MUST be run. You can search S/O for groovy scripts to rerun all jobs.
ps: you should probably consider u/g to 2.x; much better.
