Over the last week two vacuum leaks have been found in sectors 8-1 and 2-3 (Sector 7g is still holding). The leaks are similar to each other in position and therefore in likely cause. Unfortunately, these leaks are in already chilled down parts of the LHC and they will have to be warmed up to make repairs.
The delay will probably be a couple of weeks, so a planned (hoped for) October startup will now likely be mid November.
The details can all be found in this report.