Filers in the Patent Cooperation Treaty, Madrid Protocol, and Hague Agreement systems (utility patents, trademarks, and industrial designs) know that it is important to keep always in mind when midnight will arrive in Geneva, where WIPO is located.
For a PCT filer, this matters because to get a same-day filing date, a PCT application being filed in RO/IB will (usually) need to be filed by 4 PM Mountain Time. The same is true for filing an Article 19 amendment. The same is true if you are using ePCT to file a Demand and Article 34 amendment.
For a Madrid filer, this matters among other things for the payment of decade renewal fees.
For a Hague filer, this matters for the the filing of an international design application at the IB.
The point of today’s post is that starting yesterday, and for the next week, you get an extra hour to get a same-day filing date. The reason is that Europe and the US carry out their daylight saving time transitions on different days that are a week apart.
This means that you could file as late as 5 PM Mountain Time (instead of the usual 4 PM) and still get a same-day filing date.
Things will return to normal a week from now, on November 5, 2016.
One thing that happens, after you file a PCT patent application, is that Form PCT/ISA/202 arrives. (Or fails to arrive.) Why do we care about Form PCT/ISA/202? I offer some thoughts here. 
As I mentioned in 
It will be recalled that on September 1, 2017 the search fee paid by US filers of PCT applications for the EPO searching authority increased from $1992 to $2099. Now it has been announced that on December 1, 2017 this fee will increase again, this time to $2238. 
A couple of weeks ago I had the great honor to visit at WIPO with the heads of some of the PCT processing teams. These are the people at the International Bureau who interact with callers (applicants and patent practitioners) who have questions and problems relating to PCT. One of the things that they mentioned to me, that I found puzzling when I first heard it, is that in recent months they have received ever-increasing numbers of complaints from people who call to report that they try to send faxes to the International Bureau and are unable to do so. Upon reflection I now realize the likely cause of this problem. And it is definitely not that there is some recent malfunction in WIPO’s fax machines.