OPCW released an interim report on Jul 6:
OPCW designated labs conducted analysis of prioritised samples. The results show that no organophosphorous nerve agents or their degradation products were detected in the environmental samples or in the plasma samples taken from alleged casualties. Along with explosive residues, various chlorinated organic chemicals were found in samples from two sites, for which there is full chain of custody. Work by the team to establish the significance of these results is on-going. The FFM team will continue its work to draw final conclusions.
So basically: no nerve gas, but chlorine. There's no timeline specified in there for the final report.