Bluetooth Versions Compared: 4.0 to 6.0, LE Audio and What Actually Changed
Bluetooth version numbers show up on every phone, laptop and earbud spec sheet, and they tell you less than you’d think. The Bluetooth SIG (Special Interest Group), the industry body that owns the standard, publishes a Core Specification every so often; “Bluetooth 5.3” on a box means the product was qualified against version 5.3 of that spec. It does not mean the product supports every feature in 5.3. Almost everything added since 4.0 is optional.
That one fact explains most of the confusion around Bluetooth speed, range and audio quality. This page lists what each version from 4.0 onward added, separates the two radios that share the Bluetooth name, and clears up the most common myths. It reflects the specs adopted as of October 2026; the latest is Core 6.3.
Two radios under one name
Bluetooth today is really two different radio systems in the 2.4 GHz band.
Bluetooth Classic (formally BR/EDR, for Basic Rate and Enhanced Data Rate) is the original. It hops across 79 channels of 1 MHz each. Basic Rate runs at 1 Mbps; Enhanced Data Rate, added in version 2.0 in 2004, adds 2 Mbps and 3 Mbps modes. Classic is what most wireless headphones, car kits and speakers have used for audio for twenty years, through profiles such as A2DP and the SBC, AAC, aptX and LDAC codecs.
Bluetooth Low Energy (LE) arrived in version 4.0 in 2010, based on a Nokia project originally called Wibree. It uses 40 channels of 2 MHz, three of which are for advertising (devices announcing themselves). It was designed for small bursts of data from devices that sleep most of the time: fitness trackers, sensors, beacons, keyboards, locks. Every Bluetooth phone since the early 2010s speaks both.
The two are not compatible with each other over the air. A dual-mode chip runs both side by side. Almost all the development since 2016 has gone into LE, which is why the newest audio standard, LE Audio, runs on LE rather than Classic.
Version by version
| Version | Adopted | Key additions |
|---|---|---|
| 4.0 | June 2010 | Bluetooth Low Energy, GATT (the attribute model every LE device uses), AES encryption for LE |
| 4.1 | December 2013 | Better coexistence with LTE radios, devices that act as hub and peripheral at once, LE connection-oriented channels |
| 4.2 | December 2014 | LE Data Length Extension (bigger packets, faster transfers), LE Secure Connections (ECDH pairing), better LE privacy, groundwork for IPv6 over LE |
| 5.0 | December 2016 | LE 2M PHY (double LE data rate), LE Coded PHY (up to about four times the range at lower speed), extended advertising (254-byte adverts, up from 31) |
| 5.1 | January 2019 | Direction finding: angle of arrival and angle of departure for indoor positioning; GATT caching |
| 5.2 | December 2019 | LE isochronous channels (time-synchronized streams, the base for LE Audio), Enhanced ATT, LE power control |
| 5.3 | July 2021 | Connection subrating, periodic advertising improvements, channel classification; the old Bluetooth-over-WiFi “AMP” high-speed mode removed |
| 5.4 | February 2023 | Periodic Advertising with Responses (two-way contact with thousands of low-power devices, built for electronic shelf labels), encrypted advertising data |
| 6.0 | August 2024 | Channel Sounding (secure distance measurement), decision-based advertising filtering, monitoring of advertisers |
| 6.1 | May 2025 | Privacy improvement: randomized timing for changing the device’s private address, harder to track; power savings |
| 6.2 | November 2025 | Shorter LE connection intervals (minimum cut from 7.5 ms to 375 microseconds), Channel Sounding protection against amplitude-based attacks, LE Audio over USB (HCI), simpler over-the-air testing |
| 6.3 | May 2026 | Channel Sounding refinements (inline phase correction, per-PHY timing accuracy), a larger HCI command and event space for future features, relaxed RF requirements for dual-mode radios |
Bluetooth mesh, often lumped in with the version list, is a separate specification (first published in 2017) that runs on top of LE. It’s used mainly in commercial lighting.
Some context for the rows that matter most to buyers:
5.0 was the last version with a big headline change to the LE radio. 2M PHY doubles the raw LE rate to 2 Mbps. Coded PHY trades speed for range by adding error correction: 500 kbps or 125 kbps on the air, with about four times the range of the standard 1 Mbps mode. Both are optional, and most headphones and phones use them selectively or not at all.
5.2 looks dull on paper, but isochronous channels are what make LE Audio possible. Without them, LE couldn’t carry synchronized audio to two earbuds.
6.0 added the first genuinely new capability in years. Channel Sounding lets two devices measure the distance between them using phase-based ranging (comparing the phase of tones across many channels) plus round-trip timing as a security check. The SIG cites centimeter-level accuracy in good conditions, with early implementations around plus or minus 20 cm, and measurements out to about 150 m at maximum power. The main targets are digital car and door keys (a lock only opens when your phone is actually near, which defeats relay attacks) and item finders.
LE Audio, LC3 and Auracast
LE Audio is the new way to send audio over Bluetooth, and it runs on the LE radio. The Bluetooth SIG announced the full set of LE Audio specifications as complete in July 2022, building on the isochronous channels added in Core 5.2. It brings three main things.
LC3, the Low Complexity Communications Codec, is the mandatory codec. It replaces SBC as the baseline and delivers better sound at the same bit rate; Fraunhofer, which co-developed it, says LC3 beats SBC even at half the bit rate. Better efficiency means longer battery life for earbuds and hearing aids.
Multi-stream audio sends separate synchronized streams to each earbud instead of relaying from one bud to the other. It also supports proper hearing aids over a standard profile.
Auracast is the brand name for LE Audio broadcast. One source can broadcast to an unlimited number of receivers: a TV to several pairs of headphones, an airport gate announcement to anyone’s earbuds, an assisted listening feed in a theater. Receivers can join a broadcast by scanning for it or via a QR code.
The catch is the usual one. LE Audio only works if the phone, its operating system and the earbuds all support it. Plenty of current earbuds still use Classic audio with SBC, AAC, aptX or LDAC, and a phone labeled Bluetooth 5.3 or 5.4 may or may not support LE Audio. Look for “LE Audio” or “Auracast” by name on the spec sheet, not a version number.
Speed and range myths
“Bluetooth 5 doubled my headphone speed.” No. 2M PHY is an LE feature. Classic audio still runs on BR/EDR, whose top rate (3 Mbps raw) hasn’t changed since 2004. If your earbuds sound better than your old pair, the codec and the hardware are responsible.
“Bluetooth 5 has four times the range.” Only on LE Coded PHY, which few phones and almost no audio products use for streaming. Real range depends on transmit power, antennas, your body and walls far more than on the version number. A new phone with an old version can outrange an old phone with a new version.
“2 Mbps means 2 Mbps of file transfer.” The 2 Mbps is the on-air symbol rate. After protocol overhead, the best application throughput on LE 2M is around 1.4 Mbps in practice, and often much less depending on how the devices set connection intervals and packet sizes. Classic EDR tops out a little over 2 Mbps of real data.
“Bluetooth 3.0 was 24 Mbps.” It was, sort of. The HS (High Speed) option negotiated a connection over Bluetooth and then moved the data over WiFi (802.11). Almost nothing used it, and the feature was removed from the spec in 5.3.
“A newer version means everything is better.” Versions are a menu. A Bluetooth 6.0 chip doesn’t have to support Channel Sounding; a 5.2 device doesn’t have to support LE Audio. Check the feature list, not the badge.
“Bluetooth and WiFi don’t affect each other.” They share 2.4 GHz with WiFi, Zigbee, Thread and microwave ovens. Adaptive frequency hopping (since 1.2) lets Bluetooth avoid busy channels, and most phones coordinate their combined WiFi and Bluetooth chips internally, but a crowded 2.4 GHz band still costs both. If you have the choice, keep laptops and phones on 5 GHz or 6 GHz WiFi and leave 2.4 GHz to Bluetooth and IoT gear. The WiFi channel planning guide covers keeping the 2.4 GHz band clean, and noise from nearby radios is one reason dBm readings can look fine while links still perform badly.
Where Bluetooth turns up beyond headphones
Bluetooth LE quietly does work you might not notice. It’s the setup radio for most smart home gear: Matter devices typically use LE during commissioning to receive their WiFi or Thread credentials before switching over, as explained in Matter and Thread explained. Signing in with a passkey on a laptop by scanning a QR code with your phone uses an LE advertisement to prove the phone is physically nearby; passkeys explained covers that flow. Maker boards like the ESP32 and the Raspberry Pi ship with LE radios built in, which is why so many hobby sensors use it (see the Raspberry Pi guide and the Arduino ecosystem guide).
What’s next
As of October 2026 there is no Core 7.0; the newest adopted spec is 6.3. Several projects in the SIG’s pipeline are worth watching. High Data Throughput aims to push LE well past 2 Mbps, with data rates up to 8 Mbps, aimed at lossless audio and bigger transfers. A separate effort would let Bluetooth LE operate in the 5 and 6 GHz bands, easing pressure on the crowded 2.4 GHz band. An IP link protocol for carrying IPv6 directly over LE is targeted for adoption in late 2026. LE Audio work continues on lossless and spatial audio and broader Auracast coverage.
Treat these the same way you’d treat a draft WiFi standard (the WiFi standards timeline shows how long that road can be): features arrive in a spec, then in chips, then in phones and earbuds, often years apart. For now, the version number on your next pair of earbuds matters less than three plain questions: does it support LE Audio, which codecs does it use, and does your phone support the same.