It looks as if BlackBerry (BBRY) is planning a successor to its entry-level Curve line of smartphones. Earlier this week, it was reported that the company is working on a low-end BlackBerry 10 device, claimed to be part of the “R-Series.” The handset reportedly includes a QWERTY keyboard, along with 8GB of internal storage, an SD card slot, a 1,800 mAh battery and a price tag between $300 and $400. A user over at the BlackBerryOS forums on Thursday posted an image that he claims to be the upcoming BlackBerry 10 R-Series smartphone. The user gave no details on the device, although the latest rumors suggest it will hit the market later this summer or in early fall. The purported R-Series image follows below.