Now that the BBC micro:bit v2 has been announced, many people will have questions about comparability with their existing accessories and programs.
Software
Q) will my program run? Will I need to learn a New Platform?
A) Yes your program should run fine, and no you wont need to learn a new platform.
Think of this as a upgrade in options, you have a more powerful board with all the same software and platforms.
This update is all the good things of getting a new learning tool without forcing you to learn new software or having to retrain teachers.
Hardware
Q) Will my Case fit? Is it the same size?
A) Yes, Very likely, the BBC Microbit has been built to the same mechanical foot print with the same edge connector and all the pins in the same place.
The only change is a slight rise in height from the speaker which should be no problem for most cases.
BBC micro:bit v2 Dimensions:
51.60mm(w) 42.00mm(h) 11.65mm(d),
Button depth to board 4.55mm,
Speaker depth to board 3.00mm
JST connector to board 5.50mm
The micro:bit foundation has also published 3D models and reference material on their GitHub.
https://github.com/microbit-foundation/microbit-reference-design