Microsoft Azure Backup Server (MABS) v3 now support SQL 2017 workloads and can be installed on Windows Server 2019.
In addition MABS v3 introduces support for TLS 1.2 and support for VMware VM backup (vCenter and ESXi 6.5 and auto-protection when new VMWare VM’s are added to a protected folder)
You can get here https://docs.microsoft.com/en-us/azure/backup/backup-azure-microsoft-azure-backup#software-package to know how to upgrade to MABS v3.