3- constraint.Where as mile stone can. 2- Flags can not update manually as Primavera automatically This is one of the tricky Primavera Interview questions. Mile stone & flags both are events rather then activities. Some client likes to use flags rather than mile stone due the following differences.update the status where as milestone Flags can not be constraint only driven by predecessor where as milestone can. This is one of the tricky Primavera Interview questions. Mile stone & flags both are events rather then activities. Some client likes to use flags rather than mile stone due the following differences. 1- With the use of flags the logic of main event can be easily tracked as these can not be created without predecessor as stand alone allocating thecan be update manually. 3- Flags can not be constraint only driven by predecessor where as milestone can. in primavera? This is one of the tricky Primavera Interview questions. Mile stone & flags both are events rather then activities. Some client likes to use flags rather than mile stone due the following differences. 1- With the use of flags the logic of main event can be easily tracked as these can not be created without predecessor as stand alone allocating the constraint.Where as mile stone can. 2- Flags can not update manually as Primavera automatically update the status where as milestone can be update manually. Q10:What are the difference between flag and milestone activity