Since the release of version 1.0 in 1999, a number of Bluetooth versions have being developed to meet the particular requirements, adding and changing specifications to provide more security, greater speed, and compatibility.
What is important to know is that each updated version of Bluetooth was backward compatible with all previous versions. This means whichever newer version you are using then it is compatible with the older version as well. The first Bluetooth compatible device appeared in 2000, and any device that only supports version 1.x is very old, very slow, and should not be purchased.
Bluetooth version 2.0 was released in 2004. It had improved security and an increase in data transmission speeds, it also required less power, allowing devices to stay on longer. When version 2.1 was released in 2007, it provided more data transmission security, even less power consumption than version 2.0 and improved the pairing system by not requiring a PIN.
In 2009, Bluetooth 3.0 came with the ability to use Wi-Fi connections which brought transfers speed of up to 24 Mbit/s – a major jump in the data transmission rate – allowing video streaming.
Released in 2010, Bluetooth 4.0 provides lower power consumption and strong power management skills. While the maximum range remains relatively unchanged at about 300 ft, speed, security, low power consumption, and device compatibility are improved. Version 4.0 products are primarily designed for devices that collect information frequently, either as much as five times a second or just once every hour, perfect for health and fitness tracking sensors, heart rate monitors, or thermostats for your automated home.
Another convenience newer forms of Bluetooth brings is compatibility with NFC chips. Both Bluetooth 3.0 and 4.0 communicate with NFC hardware in phones and laptops to make pairing as simple a tapping the two devices together. Imagine the possibility of one day configuring Wi-Fi settings on mobile gadgets just by resting them on NFC equipped routers or hooking up headsets with tablets and phones just by contact.