https://docs.iredmail.org/upgrade.iredmail.0.9.8-0.9.9.html

cd ~
wget https://dl.iredmail.org/yum/misc/iRedAPD-2.4.tar.bz2
cd iRedAPD-2.4/tools/
bash ./upgrade_iredapd.sh

cd ~
wget https://dl.iredmail.org/yum/misc/iRedAdmin-0.9.4.tar.bz2
tar xjf iRedAdmin-0.9.4.tar.bz2
cd iRedAdmin-0.9.4/tools/
bash upgrade_iredadmin.sh

cd ~
wget https://github.com/roundcube/roundcubemail/releases/download/1.3.8/roundcubemail-1.3.8-complete.tar.gz
tar xvf ./roundcubemail-1.3.8-complete.tar.gz
cd roundcubemail-1.3.8
./bin/installto.sh /opt/www/roundcubemail/