Bluetooth versions

2001 Bluetooth 1

The original Bluetooth specification provided basic connectivity for voice and data connections. Bluetooth 1.1 followed shortly afterwards, containing mostly bugfixes; in 2003, Bluetooth 1.2 added the adaptive frequencyhopping technology that helps Bluetooth avoid the worst effects of interference.

2005 Bluetooth 2

The second major release of Bluetooth introduced the “enhanced data rate” mode (EDR), raising maximum connection speeds from 721Kbits/sec to 2.1Mbits/sec. Soon afterward, Bluetooth 2.1 added easy pairing, permitting devices such as headphones to pair with no user confirmation, or by simply tapping to confirm the connection.

2009 Bluetooth 3

Bluetooth 3 massively increased the performance potential of Bluetooth with a new high-speed (HS) data-transfer mode supporting speeds of up to 24Mbits/sec. This was a bit of a cheat, though, as the high-speed channel used a separate Wi-Fi-type radio, increasing the size, cost and power consumption of the whole module. For these reasons HS was defined as an optional extra capability, and was never widely implemented – although it’s still officially supported today, under the “Bluetooth+HS” brand.

2010 Bluetooth 4

The fourth-generation Bluetooth standard brought the biggest update the technology has seen: a new “low-energy” mode known as Bluetooth LE, or just BLE.

When used with compatible devices, this slashed power consumption, in exchange for reduced bandwidth – as low as 125Kbits/sec for devices wanting to achieve the best battery life.

Three years later, Bluetooth 4.1 increased efficiency further by allowing devices to manage their own power states, and enabling them to talk directly to one another, rather than having to communicate via the host. Bluetooth 4.2 made it

possible to use Bluetooth over IPv6, rather than relying on native radio hardware – the intention being to allow IoT devices to use Bluetooth technologies over an internet or LAN connection.

2016 Bluetooth 5

The most recent major version of Bluetooth upgraded the performance of BLE, allowing data bursts of up to 2Mbits/sec within the low-power envelope. Alternatively, LE devices using Bluetooth 5 can establish longer-range connections

at lower bit rates, making Bluetooth more viable as a platform for smart home appliances.

2019 Bluetooth 5.1

The next version of Bluetooth 5 continued to focus on range, with a new mesh connection mode that allows multi-hop connections to a host. We haven’t seen any real-world products that use this capability so far, but it could allow the personal area network to extend across a whole living space or office. A new angle-of-arrival

feature was also added, allowing Bluetooth devices to detect the direction of incoming signals from paired devices, and hence perform basic location tracking.

2020 Bluetooth 5.2

Bluetooth 5.2 was a significant update, introducing the new LE Audio profile which promises higher-quality audio streaming with less power drain ( see box, above). LE Audio also includes the Auracast protocol, which allows a Bluetooth audio source to broadcast

to an unlimited number of headphones or loudspeakers.

2021 Bluetooth 5.3

The latest release enables faster switching between performance modes, so devices can sleep when they’re not in use, then “wake up” almost instantly as needed. Bluetooth 5.3 devices can also detect radio interference and choose which radio channels to use – an improvement on the previous standard, where frequency hopping was managed solely by the host.