The U.S. Patent & Trademark Office (USPTO) will be undergoing systems maintenance this weekend. Pacific Time: 5:00pm Saturday, July 18 - 2:00pm Sunday, July 19. (Eastern Time: 8:00pm Saturday, July 18 - 5:00pm Sunday, July 19).
Most of the patent and trademark electronic systems and databases (including many of the search systems) will be unavailable during the maintenance time frame. For more detailed information, please consult the USPTO systems status page :
http://www.uspto.gov/blog/ebiz/
The USPTO is also expecting intermittent service interruptions during additional maintenance to the electronic payment systems (9:00pm Pacific Friday, July 17 - 5:00am Pacific Saturday, July 18) and application information systems (9:00pm-11:00pm Pacific, Friday, July 17).
