Bluetooth ® Core 6.0 and Onward: What Changes in the Bluetooth Specification Really Mean for Developers

First: A Brief Overview of Bluetooth Core 6.x

Subsequent minor revisions to the Bluetooth Core Specification 6.0 (6.1, 6.2, and 6.3) have introduced a large number of features to improve channel sounding and much more. 

Bluetooth 6.0 (September 2024): the big architectural release:

• Introduced Bluetooth Channel Sounding, which enables precise distance measurement between two devices, plus a new PHY (LE 2M 2BT) built specifically to support it 
• Also added Decision-Based Advertising Filtering (DBAF), Monitoring Advertisers, an ISOAL enhancement, the LL Extended Feature Set, and a Frame Space update 

Bluetooth 6.1 (May 2025): privacy/power tuning layer:

• Added Randomized RPA (Resolvable Private Address), allowing more dynamic address randomization that reduces tracking risk and improves power efficiency 
• The controller now autonomously rotates private addresses at a randomized interval instead of a fixed timer, which also cuts host-processor wakeups and saves energy 

Bluetooth 6.2 (November 2025): performance and developer tooling:

• Shorter Connection Intervals, dropping the minimum from 7.5 ms down to 375 µs for faster communication 
• Channel Sounding Amplitude-based Attack Resilience for stronger RF security, HCI USB LE Isochronous Support (Bulk Serialization Mode), and Bluetooth LE Test Mode Enhancements 
• The test mode work isn't user-facing but meaningfully improves the developer/certification experience 

Bluetooth 6.3 (May 2026): refining Channel Sounding + HCI headroom:

• Channel Sounding Inline PCT Transfer, which lets the reflector send phase-aligned tones directly into hardware, cutting overhead and speeding up ranging 
• PHY-specific RTT Accuracy reporting for better PHY selection in multi-PHY ranging 
• "Running Out of Bits" expands HCI command/event-mask capacity for future scalability, and ACP/C-I Limit Relaxation aligns RF requirements between Classic and LE, simplifying design targets and enabling more power-efficient radios

For more details on the improvements, advantages, and end user examples for these features, please see the Key Features section on our main Bluetooth page. However, the main focus of this blog post is to distill all these features into five major advantages for developers that have been ushered in since the introduction of Bluetooth Core Specification 6.0. 

5 Key Takeaways for Bluetooth Core 6.x (So Far) 

In considering the totality of development on the Bluetooth specification since September of 2024, some key themes emerge for developers:

• Native Mobile support for Bluetooth ranging: As mentioned earlier in this post, previous Bluetooth-based solutions (AoA / AoD) for range and direction required multiple antennas and offered a lower level of granularity than other competing technologies. By implementing Bluetooth Channel Sounding in 6.0 (as well as refining it with Amplitude-based Attack Resilience and Inline PCT Transfer in 6.2 and 6.3), Bluetooth now offers an extremely competitive ranging methodology. And now it’s about to gain the most important form of support: native integration in mobile phones. Android now offers native Channel Sounding support as of Android 16, and iOS will add support as of iOS 27. Between these two, a massive array of devices will become part of the channel sounding pool. This strongly makes the case for adding channel sounding capabilities to every other device, as seeker devices are soon to be widely available. 
• Fine-grained control of power budgeting: Developers have more options and configurable parameters to balance their own unique implementation of the latency vs. power usage tradeoff. Randomized RPA takes the task of address rotation away from the host and onto the hardware controller, waking the host device less often. The Shorter Connection Intervals feature drops the connection interval to the sub-millisecond level for higher responsiveness and lower power usage (see our blog post where we put this feature to the test in a real-world experiment). ACP and C/I limit changes harmonize requirements between Bluetooth Classic and Bluetooth LE to enable more flexible architectures that can result in lower power consumption and better performance in crowded environments. Alternatively, the Nordic-based implementation offers OEMs the opposite: extremely high throughput via Enhanced Shockburst (see our testing on this subject here). The result of all this is many more options for OEMs in very power-sensitive applications, such as wearables or remote battery-powered sensors.
• Privacy and security built into the link layer: Those Randomized RPA and Channel Sounding Attack Resilience features mentioned above have a secondary benefit here: They take the responsibility away from customers to develop these solutions for themselves. By making these features part of the specification, this removes the need for a developer to handle these tasks at the application level. This is a rising tide that lifts all boats, in a sense: making these native to the core specification eliminates development effort for integrators and makes the entire Bluetooth ecosystem safer, removing attack vectors broadly from the Bluetooth space. 
• Reduced friction in certification across the lifecycle: Bluetooth Core Specification 6.2 and 6.3 introduced two features with a specific focus on simplifying certification testing: LE Test Mode Enhancements (Unified Test Protocol) and Running Out of Bits. LE Test Mode Enhancements introduced Unified Test Protocol (UTP) as a new, OTA-capable alternative to Direct Test Mode (DTM). In summary, it removed the dependency on a physical control interface so that manufacturers can test final production devices without physical test ports. Furthermore, the Running Out of Bits enhancement in specification 6.3 vastly expands HCI architectural limits (Supported Commands bitmask from 64 to 251 octets, LE Event Mask from 8 to 255 octets). Ultimately this means developers are future-proofed to implement new features without hardware redesigns in future product refreshes. This doesn’t just make certification easier for the first round; it makes long-term investment in the product lifecycle easier.
• Continued backwards compatibility for legacy devices: It says something about the integrity of the Bluetooth SIG’s development that this item has come to be simply expected, but it’s worth noting. These changes are, as previously, built on top of the existing specifications that have come before them, layered on top of Bluetooth Core 5.x. That means as your product evolves and your use case expands, you can integrate radios that support the new feature set on top of your existing BOM without losing access to connections with older devices. It’s part of the reason Bluetooth enjoys near ubiquitous deployment and broad compatibility with other devices. Bluetooth can support the business needs of product designers now as well as years into the future. 

Available Now from Ezurio

Ezurio is a member of the Bluetooth Special Interest Group (SIG) and is heavily invested in the Bluetooth ecosystem, with decades of experience in designing and deploying Bluetooth solutions into the field. Our latest BL54L10, BL54L15, and BL54L15µseries modules offer flexible options to leverage the latest of Nordic nRF54 silicon. Our Aurawave AW100 Auracast™ platform leverages our partnership with Cloud2GND for cutting-edge broadcast LE audio implementations. Our Vela IF310 modules bring our hardware and software excellence to Infineon’s Airoc™ CYW55310 chipset for dual-mode Bluetooth Classic and LE audio. And our BL54LM20A series modules provide even more flash and RAM from the Nordic nRF54 series with the addition of a BL54LM20A pluggable USB-C adapter for simple addition of Bluetooth LE to any device with a USB-C port. 

At every corner of the Bluetooth world, Ezurio is poised to bring the latest and greatest in Bluetooth SIG development and silicon offerings to our customers, with the experience and expertise to help bring their designs to market on time and on budget. Our pre-certifications can be leveraged for an easier route to approval, with antennas that are validated and pre-tested to pass certifications and eliminate headaches for hardware integrators. 

State-of-the-art security, Channel Sounding, LE Secure Connections, Extended Advertising, a full suite of interfaces and timers, powerful co-processors and flexible memory/storage options… Ezurio has the perfect hardware for any design, specifically tailored to the applications and environments where our customers operate. 

To learn more, visit our website: 

https://www.ezurio.com/bluetooth