The next-generation iPhone has been rumored to include an embedded LTE radio on several occasions. Until now, however, it has only been speculation and unconfirmed reports. iDownloadBlog reported on Thursday that according to code strings in iOS 5.1, the next iPhone will indeed feature 4G LTE connectivity. “Enabling 4G will end your phone call. Are you sure you want to enable 4G,” the new iOS 5.1 code said. The references to a phone call make it clear that this is an iPhone warning rather than an iPad one. In the end, the code shows that the Cupertino-based company is at the very least testing an LTE-enabled iPhone. Apple’s next-generation smartphone is expected to feature a faster processor, a larger display and a unibody aluminum case. BGR exclusively reported this past December that the handset will also feature a redesigned antenna system, and it will launch this coming fall. iDownloadBlog’s video follows below.