Ubuntu 14.04 was designated End Of Life by the vendor in April 2019. There is, unfortunately, no upgrade path to 16.04 as running the in-built update facility will remove SVM as part of the process.
Due to this, the Virtual Appliance has been rebuilt using CentOS as this has a longer life cycle. This new VA is available for download in the Software Download Area at https://ca.secunia.com/download/
'CSI' package installed on Ubuntu 14.04 LTS VA has a dependency on PHP 5.5 package. On upgrading Ubuntu, PHP 5 will be removed and in turn, CSI will be removed.
Ubuntu VA is configured to get security updates. So on upgrading VA, the boot loader is getting corrupted.
The default LAMP stack bundled in 14.04 differs from the latest version. The purpose of VA will be gone if we install LAMP stack
Why CentOS 7? The security updates for the LAMP stack are backported and maintained at par with RHEL 7 box and free of subscription.