disabled the networking capabilities on their systems, meaning DirecTiVo does not offer such features as multi-room viewing or TiVoToGo. Only the standalone systems can be networked without additional unsupported hacking. DirecTiVo units (HR10-250) can record HDTV to a 250 GB hard drive, both from the DirecTV stream and over-the-air via a standard UHF- or VHF-capable antenna. They have two virtual tuners (each consisting of a DirecTV tuner paired with an ATSC over-the-air tuner) and, like the original DirecTiVo, can record two programs at once; further, the program guide is integrated between over-the-air and DirecTV so that all programs can be recorded and viewed in the same manner. In 2005, DirecTV stopped marketing recorders powered by TiVo and focused on its own DVR line developed by its business units. DirecTV continues to support the existing base of DirecTV recorders powered by TiVo. On 8 July 2006, DirecTV announced an upgrade to version 6.3 on all remaining HR10-250 DirecTiVo receivers, the first major upgrade since this unit was released. This upgrade includes features like program grouping (folders), a much faster on-screen guide, and new sorting features. In September 2008, DirecTV and TiVo announced that they have extended their current agreement, which includes the development, marketing and distribution of a new HD DIRECTV DVR featuring the TiVo service, as well as the extension of mutual intellectual property arrangements. Since the discontinued Hughes Electronics DirectTV DVR with TiVo model HR10-250, all TiVo units have been fully HDTV capable. Other TiVo models will only record analog standard definition television (NTSC or PAL/SECAM). The Series3 "TiVo HD, and TiVo HD XL" DVRs and the Series4 "TiVo Premiere and TiVo Premiere XL" DVRs are capable of recording HDTV both from antenna (over the air) and cable (unencrypted QAM tuner or encrypted with a Cable Card) in addition to normal standard definition television from the same sources. Unlike the HR10-250, neither the Series3 nor Series4 units can record from the DirecTV service; conversely, the HR10-250 cannot record from digital cable. Other TiVo models may be connected to a high definition television (HDTV), but are not capable of recording HDTV signals, although they may be connected to a cable HDTV set-top box and record the down-converted outputs. In 2008, some cable companies started to deploy switched digital video (SDV) technology, which initially was incompatible with the Series3 and TiVo HD units. TiVo Inc worked with cable operators on a