For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/isv:B1-Systems:Horde5:rolling/openSUSE_Tumbleweed/isv:B1-Systems:Horde5:rolling.repo
zypper refresh
zypper install php5-pear-Horde_Mail
For openSUSE Leap 42.3 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/isv:B1-Systems:Horde5:rolling/openSUSE_Leap_42.3/isv:B1-Systems:Horde5:rolling.repo
zypper refresh
zypper install php5-pear-Horde_Mail
For openSUSE Leap 42.2 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/isv:B1-Systems:Horde5:rolling/openSUSE_Leap_42.2/isv:B1-Systems:Horde5:rolling.repo
zypper refresh
zypper install php5-pear-Horde_Mail
For openSUSE Leap 42.1 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/isv:B1-Systems:Horde5:rolling/openSUSE_Leap_42.1/isv:B1-Systems:Horde5:rolling.repo
zypper refresh
zypper install php5-pear-Horde_Mail
For openSUSE Factory run the following as root:
zypper addrepo https://download.opensuse.org/repositories/isv:B1-Systems:Horde5:rolling/openSUSE_Factory/isv:B1-Systems:Horde5:rolling.repo
zypper refresh
zypper install php5-pear-Horde_Mail