来源：
页之码IP
U.S. patent applications are currently in the transition stage from PDF files to DOCX format. This is also an important measure taken by the USPTO to shorten patent examination.
During this transitional phase, applicants can still submit PDF files as backup documents, and considering that applicants and agencies are not comfortable with this submission method, the USPTO has extended this transitional phase to January 17, 2024. There is currently no fee for submitting a PDF backup file.
