2017 (https://www.tinkerforge.com/en/blog/outlook-for-2017/) we started to convert our Bricklets from 10 pole connectors to 7 pole connectors. This conversion was allready done for all of the Bricklets. Some Bricks are still equipped with the 10 pole Bricklet connector. With version 3.1 the Master Brick is now also equipped with four 7 pole Bricklet connectors.
The conversion of the remaining Bricks (Silent Stepper, IMU) will be done soon, such that in the future all Brick <-> Bricklet connections will use 7p <-> 7p Bricklet cables. For new projects it will be much easier to choose the right Bricklet cable, the 7p <-> 7p Bricklet cable will allways be the right choice.
Master Brick 2.1, 10p <-> 10p and 10p <-> 7p Bricklet cables will still be available in the shop. Spare parts as replacements for old projects will be available. These parts are listed in the "legacy" category. All non legacy Bricklets in the shop now only have the 7p <-> 7p Bricklet cable option left.
In comparison to Master Brick 2.1 the Master Brick 3.1 is equipped with 7 pole Bricklet connectors, but also with USB-C instead of Mini-USB. USB-C is at least as robust as Mini-USB but also has the advantage that the USB-C cables can be attached in both directions. Therefore it is much easier to use. Additionally the Master Brick 3.1 has a switchable Brickklet power supply. That means that you are now able to switch the power of connected Bricklets on or off during runtime with the API of the Brick.
Otherwise the Master Brick 3.1 is a one-to-one replacement for the Master Brick 2.1. Up to four Bricklets can be attached to the Brick. It is possible to build stacks of Bricks with up to 9 Bricks (1x Master Brick + 8x other Bricks). Master Brick 3.1 can be used together with Ethernet-, WIFI- and RS485 Master Brick Extension to connect attached Bricks/Bricklets with other interfaces than the USB interface of the Brick.