For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/server:mail/openSUSE_Tumbleweed/server:mail.repo
zypper refresh
zypper install courier-imap
For openSUSE Factory zSystems run the following as root:
zypper addrepo https://download.opensuse.org/repositories/server:mail/openSUSE_Factory_zSystems/server:mail.repo
zypper refresh
zypper install courier-imap
For openSUSE Factory PowerPC run the following as root:
zypper addrepo https://download.opensuse.org/repositories/server:mail/openSUSE_Factory_PowerPC/server:mail.repo
zypper refresh
zypper install courier-imap
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/server:mail/15.6/server:mail.repo
zypper refresh
zypper install courier-imap
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/server:mail/15.5/server:mail.repo
zypper refresh
zypper install courier-imap