meaning of 'until' on 30 day visa extension

Hi, I extended my L type at the local PSB. they now gave me a 30day extension, "permitted to stay until 14 MAR 2016" is what it says on the new L type. Does 'until' imply that i have to leave before the 14th, or can i still fly out of china on the 14th itself?
regards,
Arne