When does the revocation of a filing receipt license become effective?
The revocation becomes effective on the date on which the notice is mailed.
The answer to this question can be found in chapter 100 of the MPEP. This chapter covers Secrecy, Access, National Security, and Foreign Filing.
The answer is from the 9th Edition, Revision 10.2019. Depending on future changes to the MPEP, the question and answer may or may not be applicable in later Editions or revisions.
This question and answer comes from section 140 of the MPEP. The following is a brief summary of section 140.
140 Foreign Filing Licenses
This section covers both expedited foreign filing licenses and retroactive licenses. Essentially, if an inventor files a patent application in the U.S., he or she may not file the same application in a foreign country prior to the passing of six months without first obtaining a foreign filing license. If the inventor files in a foreign country before the 6 month waiting period has passed without getting a license first, he or she must immediately file for a retroactive license.