There are Versions V1.1 - V1.4 on the market.
There is no problem to mix different ESC versions in one setup with one side note:
The newer versions should be used on lower positions in the cube (ESC4 and ESC3)
Put the newest version on the bottom (closest to PDB, then the older version the higher up in the stack.
ESC can be updated using BlHeli Tool.
Latest tested and stable releease: V14.8
Update instructions and links can be downloaded here: