A screenshot of an OTA test seems to suggest that HTC is already working on a sequel to the HTC Butterfly. Three different devices were found in the OTA test file which suggest this second generation device, and one of them is likely a Verizon bound HTC Droid DNA2 as well. Here's the info that was gleaned from the pic:

The information from the test shows that there are three different variants of the DLXPLUS that would translate into three different models of the HTC Butterfly 2 for different regions. For example, the DLXPLUS_WL (DLXP_WL) would probably be the model intended for Verizon. That would make this version of the phone the HTC DROID DNA 2. It has a part number of PO68100.

Other variants listed include the DLXPLUS_UL (DLXP_UL) which is expected to be an LTE enabled model with a part number of PO68200. Lastly is the DLXPLUS_U (DLXP_U) which has a part number of PO68220. This is believed to be a model of the HTC Butterfly 2 with support for CDMA and WCDMA networks and as such, would be the global version of the device.

In Japan, HTC released the HTC Butterfly J last year. Therefore, the DLXPLUS_WLJ (DLXPLUS_J) would no doubt be the HTC Butterfly J 2 for Japanese carrier KDDI. All of the models will apparently be powered by the Qualcomm Snapdragon 600 according to the information from the testing.
What do you guys think? The Droid DNA 2 could be the Verizon version of the HTC One. Stranger things have happened...

Source: PhoneArena