There are two versions of the kit: v3 and v4. The v4 board has been included in kits for about the last 6 weeks. The earlier v3 board was released 7 December 2017. There were some differences in component brands on the v3 board reflecting sourcing difficulties experienced by the manufacturer. In particular,the TDA2822 audio chip had three variants, with the middle variant having issues with self-combustion. The manufacturer estimated around 165 boards were affected.
I suspect that v1 and v2 were prototype boards only.
There are not that many differences between v3 and v4 boards and software and all peripheral components are compatible. The primary differences being the addition of any audio anti-pop circuit(5 additional parts), the replacement of the TDA2822 with an audio amp made of discrete components. There are other minor changes including the addition of test points throughout the board to make it easier to make modifications to the board.
Hope this helps.