There are now more than ten different Bluetooth versions, all of which are compatible with each other with the exception of the low energy (LE) 4.0 version. However, versions older than Bluetooth 3.0 are rarely used.
While many users and experts compared Bluetooth to a falling star, version LE 4.0 managed to revitalize the technology. With the help of the low energy protocol stack, it became possible to save an unprecedented amount of energy. This also enabled Bluetooth to be able to be used in small devices such as smartwatches, electronic door locks and smart light bulbs. Since then, this almost 20-year-old wireless standard has been regarded as one of the most important driving forces behind the Internet of Things (IoT).
Version 4.1 now allows small devices to communicate with other devices without an "intermediary". For example, a fitness wristband can directly access a heart rate monitor without having to go through a smartphone. Another innovation is the support of IPv6 which gives every Bluetooth-capable IoT device its own IP address enabling its user to access it from the Internet. However, version 4.2 is considered to be the most technologically advanced version to date. It is known for its smaller data packets as well as its faster data transfer speed, longer battery life and better security.
But it does not end there. In December 2016, SIG released the long-awaited Bluetooth 5.0 which still specializes in IoT devices and has improved upon its predecessor in very big way. It is supposed to have increased its data transfer capacity by 800% and extended its range to up to 200 meters (outside) or 40 meters (inside) while maintaining its low energy consumption. It is also expected to help further advance the development of beacons. Beacons are small Bluetooth transmitters, which can be used in museums, for example, to send additional information to visitors’ smartphones.
While the number of devices which support the new version is still rather modest, some experts are already treating Bluetooth 5.0 as a “technical milestone” which could even overtake WLAN (at least in terms of the IoT).