For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:dancermak:sle-micro/15.5/home:dancermak:sle-micro.repo
zypper refresh
zypper install criu
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:dancermak:sle-micro/15.4/home:dancermak:sle-micro.repo
zypper refresh
zypper install criu
For 15.3 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:dancermak:sle-micro/15.3/home:dancermak:sle-micro.repo
zypper refresh
zypper install criu