How difficult it is to revive or renew a patent that has been expired (due to non-payment of maintenance fees) for more than 24 months since the law changed in 2013 (it is my understanding that the unavoidable standard is no longer applicable-http://www.clm.com/publication.cfm?ID=489)? Do they actually inquire into the reason or is similar now to the unintentional delay standard where they will essentially approve it no matter what?
Your question has been posted on Nov 2016, the text below is posted in 2017; but depending on the time-lapse it might still be relevant
2590 Acceptance of Delayed Payment of Maintenance Fee in Expired Patent to Reinstate Patent [R-08.2017]
Of special relevance (from the URL given above): Petitions to accept unintentionally delayed payment of a maintenance fee in an expired patent, if expired for two years or less, can be processed electronically, and immediately, by the applicant using the EFS-Web version of the SB/66 form found on the USPTO forms website at www.uspto. gov/patent/patents-forms. An immediate decision regarding the petitions will be rendered. The EFS-Web version of the SB/66 form should not be used if applicant wishes the petition to be processed by the Office of Petitions.
If applicant does not want immediate processing, but would prefer to submit the petition to the Office of Petitions for processing in due course, or if the patent has been expired for more than two years, applicant should use PTO/SB/66 form found on the USPTO forms website at www.uspto. gov/patent/patents-forms.