Location for self-written check plug-ins in 1.2.6

Hello, where I supposed to add self written check plug-in in 1.2.6 version?


it is newer version, and when I try to open doc for 1.6.0 it does not exists. So doc created for version 2.0.0. Will it work with 1.2.6?
I think it is /opt/omd/sites/site/local/share/check_mk/checks