between the newer versions of vix can't tell difference
As with OpenViX Zeus the main difference is core of the image or the OE (Open Embedded), this has undergone a lot of changes, updates and fixes (including fixes for the heartbleed bug in openssl). As a user you should not notice any differences between OpenViX Helios and OpenViX Apollo. (i.e. there are no real functional differences.)
OpenViX Helios build 017 will be the final build in the Helios series, and so Apollo takes over the reins.
But why a new image so soon, you just launched Helios?
Basically the recent update of the image OE (Open Embedded) to v 2.2, was very significant. This contains substantial changes and updates that mean you cannot use the online update feature from OpenViX Zeus build 023. Rather than asking users not to use the online update function, we have taken the step of changing the image name to ensure that users perform a fresh flash.