Upgrading from Debian 9 to Debian 10
The Incredible PBX 2021 platform requires the Debian 10 operating system. If your cloud provider only offers Debian 9 images, here’s how to upgrade.
sed -i 's/stretch/buster/g' /etc/apt/sources.list
apt upgrade -y
apt full-upgrade -y
apt --purge autoremove -y