MH17 crashed in Ukraine on the 17th July 2014, with the loss of all on board. According to reports aircraft was flying directly over the the disputed territory, at an altitude of 33,000 feet.
Eurocontrol reportedly said that they had kept the corridor open even as Ukrainian authorities banned any aircraft flying below 32,000 feet.
The historical flight paths followed by MH17 show that the flight on the 17th followed a route further to the north than previous flights, taking it over the disputed territory.
12-July, almost completely avoids Ukrainian airspace, flies to the south over the Black sea:
13th July, slightly further north, well inside Ukrainian space:
14th July, entered Ukrainian space further north, but routed far to the south of the disputed territory
15th July, similar to the previous day’s route
16th July, Way farther north, skirting the disputed territory
17th July, Further north still, directly over the disputed territory, with tragic result
As reported in some media, other airlines have routed away from the disputed territory’s airspace for months
e.g., Air India Delhi to Frankfurt
All images snapped from flightaware.com: