Patentees no longer have to overcome the "unavoidable delay" standard for reviving patents and patent applications as a result of USPTO rules that went into effect in December 2013. The rules, which implement the Patent Law Treaties Implementation Act of 2012 (PLTIA), eliminate the difficult-to-meet unavoidable delay standard as both a requirement and an option for patentees, leaving only the unintentional delay standard for reviving an abandoned patent application or expired patent.

Previously, patentees typically could not revive based on unintentional delay a patent that had been expired for more than two years for failure to pay a maintenance fee. Instead, after two years of expiration, patentees were required to establish the difficult-to-meet unavoidable delay. The new rules from the USPTO remove the two-year limitation, allowing patentees to petition to revive based upon the much more forgiving standard of unintentional delay any time during the patent term.

Although revived patents are retroactively enforceable back through the period of expiration, infringing parties may still turn to intervening rights, which continue to be available after the PLTIA under 35 U.S.C. § 41(c)(2). Intervening rights offer limited protection to those who rely on the expiration of a patent before engaging in activity otherwise covered by the patent. In some cases, intervening rights allow a party to engage in activity covered by the patent, even after it has been revived, for the purpose of recouping investments when deemed equitable by a court.

While patent and application owners will potentially benefit from the lowered revival standards, parties evaluating their freedom to operate should be mindful of the increased risk that "expired" or "abandoned" applications can more easily be revived, even two years after expiration.