Walter or Brian may want to add some information, but I'll take a hack at answering your question.
Adventure Pilot was feeling constrained by continuing development for the WindowsCE-based portable iFly devices. The limits of the hardware capability on those devices had been reached, and trying to maintain a (mostly) common code base for all the platforms they support (WinCE portables, Android, iOS, and Windows) meant that WinCE as the lowest-common-denominator was constraining what AP could do with the other platforms.
So they decided to drop development for the WinCE devices and focus on just Android and iOS. (At the time, even Windows support was going to be dropped.) Since they were making a clean break of things, they also transitioned to a new development environment that they expected to be better for the Android and iOS development they planned to pursue. AP decided to mark this occasion with a new name for the product: iFly EFB, instead of iFly GPS, to emphasize that the product had grown from its original "moving map" roots and was now a full-featured EFB.
However, after spending much time and effort in this new development environment, it became clear that the new dev env was not the shining unicorns and rainbows experience AP had expected. There were way more pits and ogres and dragons there than they had been led to believe by the marketing for the dev env product.
So AP eventually made the painful (but I think correct) decision to abandon the new dev env and iFly EFB product that had been developed there, and revert back to the last version of iFly GPS and the original development environment (and to return Windows support also). AP realized that just by dropping the WinCE support, they could implement a lot of what they had intended to do with their initial vision of iFly EFB just by continuing to build off of iFly GPS in the original development environment that they were very familiar with, while avoiding the pits, ogres, and dragons that plagued them in the other dev env they tried.
So yes, the "original" iFly EFB beta product has been abandoned, in favor of the iFly EFB product you see today. However, AP's intention is to incorporate much of what they had done/planned to do with the original beta into this second iteration of EFB. So, eventually (I think in the short-to-medium term), you can expect to see improvements in graphical performance (because the GPUs in modern tablets can now be leveraged; the WinCE devices didn't have such capability, which is an example of the kind of constraints WinCE was placing on Android/iOS development), support for native OS keyboards and cut-and-paste functions, freshened up UI design, etc., as well as the continuing efforts to add more features and capability to the product.