Root password is not changed for KVM VPS despite the successful message.
PHP Handler version is different from the supported one.
Access affected SolusVM slave node over SSH.
Update svmstack-php package:
# yum update svmstack-php* -y
Create symbolic link for
# mv /usr/bin/php /usr/bin/backup-php
# ln -s /usr/local/svmstack/php/bin/php /usr/bin/php