Bluetooth 5.1
The Bluetooth 5.1 upgrade was released in January 2019, enabling devices to locate connected devices within a short distance and determine where a signal originates. Enhancing location-based services improved navigation and tracking capabilities in indoor environments.
Other updates included Generic Attribute Profile (GATT) caching, which changed how devices handle repeated data transfers, reducing power consumption, enhancing advertising capabilities, and improving coexistence with other wireless technologies. Bluetooth Low Energy (LE) Audio was also enhanced for better audio quality and synchronization.
Bluetooth 5.2
Bluetooth 5.2, released in early 2020, focused on improving audio quality.
Bluetooth Low Energy Power Control was introduced to optimize power consumption in low-energy devices. It also introduced the Low Complexity Communication Codec (LC3) feature, which provided higher audio quality, enhancing music streaming and gaming experiences. Together, these two components power Bluetooth Auracast, which enables simultaneous audio streaming from one device.
Bluetooth 5.2 also introduced the Enhanced Attribute Protocol (EATT). Previously, Bluetooth devices inefficiently traded attribute data to convey information about their status and capabilities. EATT streamlined the process of exchanging this data, making it more direct and resource-efficient and optimizing the communication channel.
Bluetooth 5.2 also introduced Cross-Transport Key Derivation, a protocol that simplifies the management of encryption keys across multi-transport devices, thus enhancing security.
What Is Bluetooth 5.4?
Bluetooth 5.4 is the latest version, officially released in early 2023. It has a few updates that improve Bluetooth's functionality by enabling bidirectional and secure communication between low-power devices. These features include:
Periodic Advertising with Responses (PAwR). Broadcasts data in small packets sent within sub-events that can be synchronized with and responded to by observers. This allows observers to scan for data only at specific times and thus be more power efficient.
Encrypted Advertising Data. A standard method for advertising-data encryption that allows for partial or full encryption of shared data. This means any Bluetooth-enabled device can receive advertising data from a host, but only those with the decryption key (authorized devices) can access the encrypted data.
Low Energy GATT Security Levels Characteristic. It allows devices to communicate the required security levels for access before attempting to access specific attributes. If the device doesn't meet the security level, the client prompts them to upgrade it and gain access. This system prevents interruptions in application transitions, offering a smoother and more secure experience.
Advertising Coding Selection. Enables a host device to determine the coding system to use when transmitting advertising data to a controller. This enhancement provides more control over the balance between data rate and range, allowing for optimized performance based on specific communication needs.
All these advancements are particularly useful for high-volume use cases such as retail Electronic Shelf Label (ESL) applications where there's a multitude of connected and synchronized devices but will filter down into consumer tech products like headphones and earbuds, too.