It is very difficult to tell, something like hook a duck!
I just got one from amazon and it is a new version so can't be flashed
There's suggestions of ways to tell without opening the case however. I can't vouch for this as I have only seen mine in the flesh, but various forums seem to suggest (can't take credit for these just pooling information):
- Where "Note" is displayed on the instruction label, if it is a black exclamation mark on a light triangle its v1, reversed its v1.1 (not flash able)
- If the connectors for the power in & sensor on the back of the unit are almost touching then its v1, with a 5mm(ish) gap its 1.1
I can confirm that on my non flash able unit, both of these are true (white exclamation mark on a black triangle, connectors separated slightly)
If these turn out to be repeatably true, then I guess people could always return the units without having to crack them open to find out?