Correction: Judging from the scheme booklet, looks like anyone still short actually still has 3 more days to close out:
"Aconex intends to apply to ASX for Aconex Shares to be suspended from official quotation from close of trading on the Effective Date (which is currently expected to be Thursday, 15 March 2018). You will not be able to sell your Aconex Shares on market after this time."