You have the Duo (v1) which was on the market for years. The Duo v2 was released to the market in late 2011.
The Duo (v1) and NV+ (v1) are sparc based and the version of RAIDiator is 4.1.x.
The Duo v2 and NV+ v2 are ARM based and the version of RAIDiator is 5.3.x.
The two cannot be mixed. If you ever add a new Duo v2 to your setup, be aware that you cannot simply pull the drives from a v1 and install in a v2 as the formatting is incompatible.
RAIDiator 4.1.8 is the latest released version for the v1 although 4.1.9 is in Beta testing.
There is no models with the Duo or NV+ name in the x-86 based lines (Pro and Ultra lines only with 2, 4. and 6 bays). Older discontinued models in this architecture are the old 6 bay Pros and 4 bay NVXs. The version of RAIDiator with the x-86 based units is 4.2.x.
Yes if you have all your data backed up its not a bad idea to do a factory reset get a nice clean install on new hard disks. well you will have to do a factory reset to set up with X-RAID because if you only had 1 disk in it will be setup as flex raid or jbod.
Yes i agree it is a bit confusing added with the RND2xxx labeling which only indicates if it was a diskless unit or hard disks installed on purchase. i am glad i had a good read of all the documentation before i purchased mine.
When the v2 series was released with the same names, there was a howl on the forums about the confusion that would reign. The development staff told us they tried to get the marketing people to understand that, but apparently they wanted to build on the reputation of the originals. Marketing types don't listen to engineers. There was mild confusion between the original Pro models (BE and Pioneer) and the Pro 6 when it was released, but at least the disks can be moved between them and they both use the same version of RAIDiator. I think we will be dealing with the v1 vs v2 confusion for years.