Yes. Prior art still invalidates patents under first to file.
Actually, the system is harder now in some ways (and easier in others) because it's closer to "first to publish" than other "first to file" systems:
> an applicant could file a U.S. patent application covering an invention that was the subject of a publication provided the publication was dated less than 1 year earlier. This was true even if the publication was by another individual or entity that independently arrived at the invention on his or her own. Effective Saturday, March 16, 2013, if another individual or entity independently arrived at the invention and published an article before the first inventor filed the first inventor who filed will be unable to obtain a patent.
A lot of the people calling "end of world" around "first to file" don't really know what the new system means (not their fault, it's complicated!). What first to file does is mean that if you keep your invention secret, you can't then claim it as prior art for someone else down the road or claim that you actually deserve the patent because you invented it first. At least in this way, it makes uncertainties around patents a lot fewer.
Actually, the system is harder now in some ways (and easier in others) because it's closer to "first to publish" than other "first to file" systems:
> an applicant could file a U.S. patent application covering an invention that was the subject of a publication provided the publication was dated less than 1 year earlier. This was true even if the publication was by another individual or entity that independently arrived at the invention on his or her own. Effective Saturday, March 16, 2013, if another individual or entity independently arrived at the invention and published an article before the first inventor filed the first inventor who filed will be unable to obtain a patent.
http://www.ipwatchdog.com/2013/03/16/a-brave-new-patent-worl...
A lot of the people calling "end of world" around "first to file" don't really know what the new system means (not their fault, it's complicated!). What first to file does is mean that if you keep your invention secret, you can't then claim it as prior art for someone else down the road or claim that you actually deserve the patent because you invented it first. At least in this way, it makes uncertainties around patents a lot fewer.