through a wired Ethernet network, or a mixture of the two. The Sonos system creates a proprietary AES-encrypted peer-to-peer mesh network, known as SonosNet. This allows for each unit to play any chosen input and if desired share it as synchronized audio with one or more other chosen zones. The first versions of SonosNet required a single ZonePlayer or ZoneBridge to be wired to a network for access to LAN and Internet audio sources or when creating a 3.1/5.1 surround setup. SonosNet 2.0 integrated MIMO on 802.11n hardware, providing a more robust connection. Later, the company added support for connecting to an existing Wi-Fi network for internet connectivity, removing the wired network requirement. S1 and S2 operating systems In 2020, Sonos released its S2 operating system. Its existing system was renamed "S1" to differentiate it from its new system. All products launched after May 2020 support S2 exclusively. Trueplay In November 2015, a tuning feature called Trueplay was released in a software update. Trueplay tunes the output of Sonos smart speaker units to the acoustics of the room they are in. The initial tuning process requires the use of a suitable Apple smartphone or tablet. Standby and Low power mode Sonos devices generally do not have power buttons, and the company claims that each speaker consumes 4–8W in idle/standby. Its battery-powered lineup does have power buttons to turn them on and off. Reception In November 2004, the Sonos Digital Music System won the "Best of Audio" award at the 2005 CES Innovations Design and Engineering awards. A February 2005 Macworld review of the first Sonos system explained its background, components and operation. Support for the CR100 ended in 2018 when Sonos sent out an update that intentionally caused the CR100 to cease to function, resulting in expressions of unhappiness from a number of long-time Sonos customers. Sonos later settled a class action lawsuit related to its decision to intentionally cause the CR100 to cease to function. Sonos was criticized by media outlets in December 2019 for its "Recycle Mode", which bricks devices that users register into the company's trade-in program. Customers who participate in the program receive a 30 percent discount on a purchase of a new Sonos device, but the registration puts the device into Recycle Mode, which starts a timer that turns the device permanently non-functional in 21 days. An electronic waste recycler criticized the procedure on Twitter