Bluetooth versions: BT 4.2 (legacy IoT), BT 5.0 (4× range, 2× speed), BT 5.2 (LE Audio, Auracast), BT 5.3 (improved efficiency), BT 5.4 (range, security).
Bluetooth 5.0 (2016): doubled speed (2 Mbps), 4× range, Bluetooth Mesh. Bluetooth 5.1 (2019): direction finding (centimeter-level accuracy). Bluetooth 5.2 (2020): LE Audio, LC3 codec (better quality at lower power), Auracast broadcast. Bluetooth 5.3 (2021): connection subrating (battery savings), encryption improvements. Bluetooth 5.4 (2023): periodic advertising responses, electronic shelf labels.
For pairing music devices, BT 5.0+ is fine. LE Audio (5.2+) enables hearing aid compatibility and shared audio. The codec used (SBC, AAC, aptX, LDAC) usually matters more than the BT version.