Bluetooth 4.0 was introduced almost a decade ago in 2010 and brought about some notable improvements, such as Bluetooth low energy (BLE). Bluetooth 4.0 allows smaller devices like headphones, fitness trackers, and hearing aids to stay connected for longer while using less power. In contrast, the older Bluetooth would use lots of energy. Bluetooth 4.0 can now more intelligently manage these connections and put them to sleep when they're not in use. Bluetooth 4.0 also came with Bluetooth intelligent, ready devices, so these are the primary devices like laptops/phones/tablets. It allowed these devices to act as a hub sending and receiving information from all Bluetooth-connected gadgets.
Bluetooth would struggle to exist parallelly with 4G, also known as LTE; Their signals would overlap and interfere, which would degrade the overall performance and use more battery life. The introduction of 4.1 solves this problem, ensuring that your 4G and Bluetooth connections do not overlap. Another notable improvement with 4.1 is that all of your devices could now act as the endpoint and the hub. This means your Bluetooth-enabled gadgets didn't have to connect through your primary device; they could communicate directly with each other.
Bluetooth 4.2 saw a massive improvement in speed as data transmission was two and a half times faster. It also increased the number of packets, or the amount of data sent tenfold. Still, perhaps Bluetooth 4.2's most significant improvement was introducing internet protocol version 6 (ipv6). It allows Bluetooth devices to connect to the internet directly, which played a big part in bringing about the era of IoT. Now anything from lights to thermostats to fridges can connect directly to the internet and be controlled by you remotely. Besides these, there were some other power management and security improvements.
With Bluetooth 5 in 2017 came another doubling of speed; now 2 MB/s over the 1 MB/s of Bluetooth 4.2. The range received a massive upgrade too Bluetooth 4.2 could manage a maximum distance of 60 m/240 feet, Bluetooth 5 raised that to 240 m/800 feet. Dual audio also made its appearance, so this lets you play audio on two connected devices simultaneously. For example, you could have two Bluetooth speakers connected to your phone simultaneously and play audio to both speakers. This also allows the devices to become stereo pairs.
Bluetooth 5.1 was introduced in 2019, and new in this version was the ability for Bluetooth devices to pinpoint your location. It is what allowed Bluetooth-enabled smart tags to enter the market. You can attach your essential belongings and get a rough estimate of their location based on the Bluetooth connection. It also did bring a few more enhancements, such as improving the speed of the Bluetooth pairing process while reducing the amount of power.
Bluetooth 5.2 came about a year later and focuses primarily on making improvements to audio devices. There's a new generation of Bluetooth audio called LE audio, presumably low-energy audio. With this, a new audio codec called lc3 apparently can provide high-quality audio while using low power. It also allowed multiple synchronized data streams. In the past, only one of your wireless earbuds would be connected to your phone, while the second earbud would connect to the first. Having both buds connect directly to your phone improves the reliability of your connection. It eliminates any delay or synchronization issues there may have been between left and right channels. Also, Bluetooth 5.2 can now go much longer on a single charge.
With all these, we know that Bluetooth 5 and series have provided some serious upgrades to the communication of IoT devices. It also supports low-energy audio, which can be a new standard for audio transmission in the future.