http://raytaccorp.blogspot.tw/2016/08/what-is-difference-between-bt41-bt42.html
BT4.1
- Improving Usability—extends the brand promise to consumers with an “it just works” experience. This spec is engineered with several new features to make it work seamlessly with popular cell technologies like LTE, maintain connections with less frequent manual reconnection, and deliver a more efficient data exchange.
- Empowering Developer Innovation—provides developers with greater flexibility to create innovative Bluetooth products and solutions through dual-mode topology and link-layer topology software features.
- Enabling the Internet of Things—lays the groundwork for IP-based connections by allowing devices to setup a dedicated communication channel in the future thereby extending the central position for Bluetooth technology in the Internet of Things.
BT4.2
- Privacy and Security
Bluetooth 4.2 introduces industry-leading privacy settings that lowers power consumption and builds upon the government-grade security features of the Bluetooth specification. The new privacy features put control back into the hands of the consumer by making it difficult for eavesdroppers to track a device through its Bluetooth connection without permission. For example, when shopping in a retail store with beacons, unless you’ve enabled permission for the beacon to engage with your device, you can’t be tracked.
- Speed
Bluetooth 4.2 increases the speed and reliability of data transfers between Bluetooth Smart devices. By increasing the capacity of Bluetooth Smart packets, devices transfer data up to 2.5 times faster than with previous versions. Increased data transfer speeds and packet capacity reduces the opportunity for transmission errors to occur and reduces battery consumption, resulting in a more efficient connection.
- Internet Connectivity
Building on the capabilities released earlier with Bluetooth 4.1 and the new features released in 4.2, the Internet Protocol Support Profile (IPSP) will allow Bluetooth Smart sensors to access the Internet directly via IPv6/6LoWPAN. IP connectivity makes it possible to use existing IP infrastructure to manage Bluetooth Smart “edge” devices. This is ideal for connected home scenarios that need both personal and wide area control. This profile will be ratified by the end of the year.