When you buy a Bluetooth module, the Bluetooth core specification version on the datasheet decides which features you actually get. Vendors print “5.3” or “5.4” prominently, but a version label is not a feature list. This article maps each spec revision to the concrete radio, PHY, and protocol capabilities that change range, throughput, direction finding, audio, and security, so you can pick a module by what your firmware will actually use.
Bluetooth 5.0 (2016)
The first major LE overhaul:
- 2M PHY: doubles the symbol rate to 2 Msym/s. Raw over-the-air throughput roughly doubles versus the 1M PHY.
- LE Long Range (Coded PHY): S=2 and S=8 coding add forward error correction. S=8 gives about +12 dB link budget, which in free space is ~4x theoretical range (realistically 2-3x).
- Advertising Extensions: larger advertising packets (up to 255 bytes in extended, with chainable aux packets), and Periodic Advertising for connectionless, deterministic broadcasts.
Bluetooth 5.1 (2019)
- AoA / AoD Direction Finding: the addition of the Constant Tone Extension (CTE) lets a receiver sample IQ data at 1 MHz per antenna and estimate angle. AoA needs a switchable antenna array at the receiver; AoD needs it at the transmitter.
- This is the version that turned a plain Bluetooth module into a positioning asset, but only if the silicon exposes CTE and the board ships with (or supports) an antenna array.
Bluetooth 5.2 (2020)
- LE Audio: isochronous channels and the LC3 codec, enabling broadcast audio and lower-bitrate high-quality sound.
- EATT (Enhanced ATT): runs ATT over a separate L2CAP channel with improved security and parallel transactions, fixing the old single-bearer stalls.
- LE Power Control: graded TX-power adjustment between peers, cutting near-field power and improving coexistence.
Bluetooth 5.3 (2021)
- Periodic Advertising with ADI: duplicate filtering at the link layer reduces wasted scans.
- Connection Subrating: drop to a low duty cycle instantly and ramp back up fast, better than renegotiating intervals.
- Channel Classification Enhancement: the peripheral can tell the central which channels are bad, so the link avoids them.
- Encryption key size enforcement: rejects links that try to negotiate below the minimum.
Bluetooth 5.4 (2023)
- PAwR (Periodic Advertising with Responses): connectionless two-way, designed for Electronic Shelf Labels and massive broadcast networks where thousands of tags reply in scheduled slots.
- Encrypted Advertising Data (EAD): encrypts the payload while still letting unpaired scanners see the header.
- LE GATT Security Levels: finer control over which attributes require which security.
Feature Matrix
| Feature | 5.0 | 5.1 | 5.2 | 5.3 | 5.4 |
|---|---|---|---|---|---|
| 2M PHY | Yes | Yes | Yes | Yes | Yes |
| LE Long Range | Yes | Yes | Yes | Yes | Yes |
| AoA / AoD | No | Yes | Yes | Yes | Yes |
| LE Audio / LC3 | No | No | Yes | Yes | Yes |
| EATT | No | No | Yes | Yes | Yes |
| LE Power Control | No | No | Yes | Yes | Yes |
| Connection Subrating | No | No | No | Yes | Yes |
| Channel Classification | No | No | No | Yes | Yes |
| PAwR | No | No | No | No | Yes |
| Encrypted Adv Data | No | No | No | No | Yes |
Throughput and Range Math
- 1M PHY raw ~1.4 Mbps; application throughput after overhead ~0.27 Mbps. 2M PHY roughly doubles both.
- Coded PHY S=8 raw ~125 kbps, but the +12 dB budget is the point: at 1M PHY a link closes at -92 dBm; with Coded S=8 the same receiver tolerates ~-104 dBm, extending range by about 4x in ideal path loss.
- Rule of thumb: every +6 dB roughly doubles range in free space, so +12 dB is ~4x, but walls and noise eat half of that in practice.
Minimum Version by Use Case
| Use case | Minimum version |
|---|---|
| Beacon / advertising-only | 5.0 |
| Finder with angle (AoA) | 5.1 |
| Headset / LE Audio | 5.2 |
| Power-optimized sensor mesh | 5.3 |
| ESL / mass 2-way broadcast | 5.4 |
Pitfalls
- “5.3 module” does not mean LE Power Control is enabled; the vendor must implement it.
- Older silicon sometimes predates the spec it claims; check the Qualified Design ID (QDID) on the SIG website.
- A module can be SIG-qualified for a version yet ship a firmware that disables the feature.
- Buying 5.4 “just in case” wastes BOM when 5.0 covers the job.
Pick the version by the feature your firmware calls, not the biggest number on the box. For a qualified reference, our Bluetooth module lineup documents which Bluetooth features each part actually implements.