In previous postings I have mentioned reasons why filers should use ePCT, WIPO’s system that lets you see the status and content of your pending PCT applications. Here are three more reasons.
The ePCT system allows you to apply a wide range of filters and to generate reports based on the filters. Quoted below are screen shots showing some of the available filter settings.
For example you could look for all of your cases in which the International Bureau has not yet received Form PCT/ISA/202 (the form in which the International Searching Authority acknowledges receipt of the Search Copy).
For important cases you might wish to follow up with the RO and with the ISA. After all, any delay in the “receipt date” listed in the Form ISA/202 will lead 
to a corresponding delay in establishment of the ISR/WO (international search report and written opinion) that might later get you onto the Patent Prosecution Highway.
As another example you could look for all of your cases in which the IB has not yet received a certified copy of a priority document.
This can be important, since if it was your responsibility to provide a certified copy to the IB, and if you fail to do it timely (roughly, by the sixteenth month) then you risk a complete loss of your priority claim.
If your way of getting the certified copy to the IB is by means of DAS, then this report can prompt you to look further to try to figure out what went wrong in the DAS process.
If your way of getting the certified copy to the IB is by “checking the box” and asking the RO to transmit the certified copy, then this report can prompt you to make inquiry at your RO to see what went wrong.
A third kind of helpful report is the report listing applications that were filed with RO/IB and for which one or 
more fees is outstanding.
This report can prompt you to go and find that email from the IB with the payment link in it.