There's no default context (anymore)
Since the possible contexts have been reduced to "Production" and "Development" you get the following error, if you didn't provide any context:
"FLOW3: Unknown context "" provided, currently only "Production" and "Development" are supported. (Error #1254216868)"
Ppl that are new to FLOW3 and just downloaded the distribution will be very confused about that. They don't get any hint to the tutorial anymore, because there's no welcome screen.
If there's no context defined, Production should be default.