A Comprehensive Guide on Different Bluetooth Versions

The sky is blue, the sea is blue, and apparently Bluetooth is blue too. In 2023, the global shipments of Bluetooth devices reached an astronomical 5.4 billion units! That number just keeps skyrocketing year after year. From transmitting audio and text/images, all the way to streaming video and powering low-energy IoT connections, Bluetooth technology has seriously made life way more convenient for people everywhere. It provides this crucial way for connected devices to communicate data without cables. In this article, we’re going to look back at how Bluetooth versions have evolved from 1.0 to 5.0, and explore the increasing applications. If you’re clueless about this ubiquitous wireless tech, prepare to be enlightened by different Bluetooth version!

What is Bluetooth technology?

Bluetooth is an open global standard for wireless data and voice transfer, which aims at enabling low-cost, short-range wireless connectivity among different electronic devices.

Origins of Bluetooth technology

The origin of Bluetooth technology can be traced back to as early as 1942 when an application for the use of the FHSS (frequency-hopping spread spectrum) was patented by actress Hedy Lamarr alongside composer George Antheil. The idea of this patent is to expand the range of signal frequencies that influence the torpedoes to 88 ones which will make the process more secure and less suffer from interferences. But the military later adapted it for wireless communication during the war, and further development transformed it into the basis of modern wireless technologies such as Bluetooth, WiFi, and 3G.

Bluetooth is named after the medieval Danish king Harald Bluetooth Bluetooth who united the divided kingdoms of Denmark and Norway. This name means integration and interaction of multiple disparate devices. Jim Kardach of Intel proposed the term Bluetooth; The Bluetooth logo is the initials HB, from Harald’s bestowed name and is represented by old Norse script.

A brief history of Bluetooth technology development

• In 1994, Ericsson started working on what became a low power wireless interface for the phones and their accessories.
• In 1998, Ericsson, IBM, Intel, Nokia and Toshiba formed the “Bluetooth Special Interest Group” to establish standards for short-range radio.
• 1999 saw the Bluetooth 0.7-1.0 spec releases designating 2.4GHz and defining core protocols.
• In the last half of 1999, Microsoft, Motorola, and others joined the promotional efforts, sparking global Bluetooth adoption. The alliance has reached over 1,500 members by the year 2000.
• 2001: 1. 1 IEEE 802.15.1.
• 2003: 1. 2 introduced adaptive frequency hopping.
• 2004: 2. 1 adopted EDR, with a maximum transfer rate of 3Mbps.
• 2007: 2. 1 Secure paring/connection, introduced NFC.
• 2009: 3. 0 integrated with WiFi, 24Mbps speed.
• 2010: 4.0 opted for Bluetooth low energy.
• 2013: 4. 1 support for LTE.
• 2014: 4. 2 support IPv6 and 6LoWPAN.
• 2016: 5. 0 doubled speed, extended range.
• 2019: 5. 1 enhanced location, power management.
• 2020: 5. 2 supported LE Audio, EATT.
• 2021: 5. 3 added connection subrating for frequencies.
• 2023: 5. 4 added PAwR and EAD
• By 2023, the Bluetooth SIG had more than 40, 000 members.
• 2024, Bluetooth 6.0 is coming.

Bluetooth has evolved and upgraded through multiple different Bluetooth versions with enhanced wireless communication performance and broader application scope.

Classic Bluetooth versions: Bluetooth 1.0 – 3.0

Bluetooth 1.0

In July 1999, the Bluetooth SIG officially introduced the Bluetooth 1.0 specification, advancing the technology to a commercially viable stage. The Bluetooth 1.0 standard primarily targeted point-to-point wireless connections such as wireless communication between mobile and computing devices, computers and peripherals, mobile and headsets, among others.

The original Bluetooth 1.0 spec laid out the basic features, but it didn’t give enough detailed instructions on how to actually put it into practice. This made it really tough for different devices to work well together. Because of these interoperability issues, Bluetooth 1.0 couldn’t live up to the hype and didn’t get picked up as widely as hoped across the tech world.

Bluetooth 1.1

The non-official 1.1 version was introduced in October 2000, extending functionality to support point-to-multipoint connections and addressing issues present in version 1.0. The official 1.1 specification was subsequently released in March 2001. To ensure secure communication, Bluetooth employs encryption where devices exchange keys during connection establishment to authenticate identities. Communication cannot occur if key verification fails. Bluetooth 1.1 resolved the contention issue of devices vying for master-slave roles in version 1.0 by clearly defining the pairing process.

It standardized the use of 79 channels in the 2.4GHz frequency hopping scheme across all regions. Additionally, slave devices could report supported channel counts and packet sizes to allow transmission parameter adjustment.

Bluetooth 1.2

In November 2003, Bluetooth SIG released the Bluetooth 1.2 specification. As Bluetooth 1.1 was vulnerable to interference by 802.11b wireless LANs, version 1.2 introduced AFH (Adaptive Frequency Hopping) to reduce interference with Bluetooth devices and other wireless communication equipment. Moreover, Bluetooth 1.2 devices that extended the ESCO (Enhanced Synchronous Connection-Oriented) link type for voice/audio transmission were also identified.  Although providing the possibility of faster connection, it was still compatible with Bluetooth 1.1 devices.

Bluetooth 2.0

Bluetooth 2.0, which was released in November 2004, has introduced the EDR (Enhanced Data Rate) technology, which is a major step forward from version 1.2. EDR increased the data transfer rates up to 3Mbps and trebled bandwidth compared to the preceding version. This made the transfer of large files to be twice as low power as that of Bluetooth 1.2. Bluetooth 2.0 supported full-duplex communication, which enabled the transmission of both voice and data at the same time. It also extended the multi-device connection capability.

Bluetooth 2.1

In March 2007, at CTIA Wireless 2007, the Bluetooth 2.1+EDR standard emerged. A key feature was NFC integration for simplified pairing by transmitting passwords without manual input when devices were in close proximity. The Sniff Subrating feature conserved power by extending the signal confirmation interval between devices from 0.1s to 0.5s. Additionally, Secure Simple Pairing (SSP) improved the pairing experience while enhancing usability and security.

Bluetooth 3.0

In 2009, the Bluetooth SIG introduced Bluetooth 3.0 + High Speed (HS), maintaining version 2.0 feature compatibility. The key addition was an optional High Speed extension leveraging the IEEE 802.11PAL (Protocol Adaptation Layer) to support up to 24Mbps throughput  – 8x faster than Bluetooth 2.0’s 3Mbps maximum.

The core innovation was Alternate MAC/PHY (AMP) – enabling the Bluetooth stack to dynamically utilize the appropriate radio for a given use case. This brought some improvement in power optimization with the EPC (Enhanced Power Control) and offloading larger transfer to 802. 11’s lower idle mode. Moreover, the emergence of UCD (Unidirectional Connectionless Data) helped improve broadcast features.

Bluetooth low energy versions: Bluetooth 4.0 – 5.4

Bluetooth 4.0

In December 2009, Bluetooth 4.0 was unveiled – a comprehensive tri-mode integration of Classic Bluetooth, High Speed, and the innovative Bluetooth Low Energy (LE) extension.

The key breakthrough was LE. It reduces power consumption by up to 90% via an ultra-low power idle mode using an optimized low bandwidth protocol stack tailored for IoT devices. This meant IoT sensors and gadgets could run for years on a tiny coin cell battery.

BLE also offered 3ms low latency, over 100m range, AES-128 encryption and other robust connectivity capabilities. In parallel, High Speed allowed for high throughput, utilizing 802.11 radios, while Classic Bluetooth remained backward compatible.

This tri-mode approach allowed for optimization versatility in terms of data rates, namely High Speed for the high bandwidth utilization in LAN applications, LE for the ultra-low power IoT, and Classic for the original streaming application.

Bluetooth 4.1

Introduced in 2013,  Bluetooth 4. 1 was a major release that brought improvements revolving around IoT, mainly to bring ubiquitous connectivity to devices. Building on Bluetooth 4.0 LE, it offers higher throughput for transfer of bulk data which is perfect for wearables such as fitness trackers. Devices can simultaneously operate as “Bluetooth Smart” and “Bluetooth Smart Ready,” enabling multi-device connections.

Furthermore, Bluetooth 4.1 also introduced support for coexistence with the latest cellular technologies including LTE to enable smooth interconnectivity. It incorporated IPv6-based cloud synchronization support, addressing IoT application requirements.

Bluetooth 4.2

Launched in 2014, Bluetooth 4.2 introduced a more substantial step by supporting internet connection through IPv6 and 6LoWPAN protocols. This innovation primarily enabled several Bluetooth devices to connect to the internet or LAN through one gateway terminal. It delivered up to 2.5x faster transfer speeds and 10x larger packet capacity compared to Bluetooth 4.1.

Notably, Bluetooth 4. 2 boosted transfer rates and privacy protection. Bluetooth signals in the new standard can only connect or track a device after receiving permission from the user. This also reassures users of the ability to use wearables fearlessly without worrying about unauthorized tracking.

Bluetooth 5.0

Bluetooth 5.0 was launched early in 2016, offering enhanced performances than the previous Bluetooth standards. It significantly improved the message capacity to 255 bytes – 8 times more than the capacity of Bluetooth 4. 2. As a result, the data transfer rate increased and went up to even 2 Mbps in low power mode, twice the earlier rates. In addition, the communication range has been extended four times as far compared to Bluetooth 4.2, in theory up to 300m.

Notably, it was also in Bluetooth 5.0 that indoor positioning and navigation were introduced and allowed for sub-meter accuracy when integrated with WiFi. Furthering the development of the previous internet landscape and IoT, it branched further into the concept of the smart home on a larger scale.

Bluetooth 5.1

Bluetooth version 5.1 was announced in 2019, which brought groundbreaking direction finding and centimeter-level positioning services. This enhancement was aimed at improving localization with the help of Bluetooth, which proved very beneficial in indoor navigation and tracking of assets, a key concern in the area.

These improvements included better GATT caching and handling of redundant data to cut down on power usage, augmented broadcast functionality, and coexistence with various wireless protocols. Bluetooth LE audio quality and synchronization were also increased by a large measure.

The earlier Bluetooths such as the 4.x, could also handle mesh networking and the beacons for asset tracking. However, Bluetooth 5.1 offers greater versatility and efficiency, which complements the aforementioned applications and can be useful for any other existing or future applications requiring higher accuracy of positioning and localization.

Bluetooth 5.2

Bluetooth 5.2 with its early introduction in 2020 was mainly focused on enhancing the audio experience. Some of the key features discussed were EATT (Enhanced Attribute Protocol), LE power control, CTKD, and LE Isochronous channel support. Notably, LE Audio enabled stereo streaming in connected and broadcast modes while enhancing Bluetooth audio performance. The integration of Bluetooth Auracase enabled users to witness a significant improvement in high-quality audio outputs.

Bluetooth 5.3

In 2021, Bluetooth 5.3 was released, featuring significant enhancements in transmission efficiency, security, and stability. Compared to Bluetooth 5.2, Bluetooth 5.3 offers reduced latency, enhanced interference resistance, and improved battery life. Notably, Bluetooth 5.3 does not alter the transmission speed or range. The following are the four key enhancements:

• Connection sub rating
• Encryption key size control enhancements
• Periodic advertising enhancements
• Channel classification enhancements

Bluetooth 5.4

Unveiled in 2023 as the latest Bluetooth version, Bluetooth 5. 4 introduced several enhancements to provide more effective, bidirectional, secure communication for low-power devices. Some of the new aspects of Bluetooth 5. 4 include:

• Periodic Advertising with Responses (PAwR): Enabling time-synchronized bidirectional networks by broadcasting small data packets within sub-events to facilitate synchronization and power savings.
• Encrypted Advertising Data (EAD) – Enabling data encryption within advertising packets. Only devices with the shared session key can decrypt EAD and the option for partial/full encryption is available to increase security.
• LE GATT Security: Allowing devices to indicate security mode and level.
• Broadcast Codec Selection: Enabling codec selection for optimized transmission of BLE extended advertisements.

Bluetooth versions comparison: Bluetooth vs Bluetooth low energy

Since version 4.0, Bluetooth technology has diverged into two distinct branches: Bluetooth Classic and Bluetooth Low Energy. The Classic Bluetooth upon which our present idea of wireless connectivity is primarily built has applications in areas such as wireless speakers, car infotainment systems, and headphones. Operating in the 2.4GHz band, it enables the devices to establish personal area networks for short-range data transmission and has become an essential technology for pairing audio devices with mobile platforms.

Bluetooth Low Energy, on the other hand, represents a significant stride in energy efficiency within the Bluetooth ecosystem. As its name suggests, BLE’s salient feature is its remarkably low power consumption and highly optimized sleep mode. While it utilizes the same 2.4GHz band as Classic Bluetooth, it uses a different FHSS scheme, resulting in a data transmission rate of approximately half that of Classic Bluetooth.

The terms BT, BR, Basic Rate, EDR, BR/EDR, and AMP are synonymous with Classic Bluetooth, while BLE, Bluetooth Low Energy, Bluetooth Smart, and LE refer to low-power Bluetooth.

Dual-mode Bluetooth, as the name suggests, is a combination of both classic Bluetooth and Bluetooth LE, allowing devices to support both standards simultaneously.

Given the popularity of small, low-power devices and sensors in various IoT applications, BLE has emerged as a more dominant Bluetooth protocol in the IoT domain. Therefore, the market has witnessed the development of dual-mode Bluetooth chips. In essence, BLE is not just a lite version of Classic Bluetooth, but a specialized iteration of energy-efficient wireless connectivity designed for power-sensitive and low data rate applications.

Future of Bluetooth: what to expect for Bluetooth 6.0

Since its inception in 1998, Bluetooth has undergone a remarkable 26-year evolution, progressing from version 1.0 to the current 5.0 release. Initially focused on audio, text, and video transmission, its scope has gradually shifted toward low-power data transmission tailored for IoT applications. While maintaining backward compatibility, a hallmark of the technology, Bluetooth has seen increasing adoption across a myriad of IoT devices.

As the BLE variant advanced in power efficiency and transmission, the classic Bluetooth version stagnated post-version 3.0. The latest major update was Bluetooth 5.0 in 2016, optimizing speed and range balance for low-power devices. Aligning with typical release cadences, Bluetooth 6.0 is anticipated within the next few years. The primary development vector is projected to concentrate on the IoT domain, transcending historical mobile device confines. The rollout of Bluetooth 5.0 and maturation of mesh technology have expanded possibilities for prospective IoT applications.

On September 3, 2024, Bluetooth SIG just issued official statements concerning version Bluetooth 6.0, introducing new enhancements and capabilities. A key highlight of this update is the Bluetooth Channel Sounding. Despite the promising Bluetooth 6.0 updates, it may take several years before the 6.0 version becomes widely available in consumer devices and IoT products. Stay patient!

FAQs about Bluetooth versions

Can a Bluetooth 3.0 device establish a connection with a Bluetooth 5.0 device?

Bluetooth 3.0 devices are inherently incapable of directly connecting to Bluetooth 5.0 devices, as they utilize disparate transmission protocols. However, certain dual-mode Bluetooth 4.0 devices can simultaneously support Bluetooth 3.0 and Bluetooth 5.0 devices.

Can a Bluetooth 5.0 device establish a connection with a Bluetooth 3.0 device?

Bluetooth 5.0 devices exhibit backward compatibility with Bluetooth 3.0 devices, thereby enabling connectivity between the two. Nevertheless, this interoperability comes at the cost of reduced transmission rates and heightened power consumption.