For two weeks after premium processing resumes for H-1B cap-subject petitions, USCIS will not use pre-paid mailers to send out final notices for premium processing H-1B cap-subject petitions. Instead, USCIS will use regular mail. USCIS will be doing this due to resource limitations as work to process all premium processing petitions in a timely manner. After the two week period, USCIS will resume sending out final notices in the pre-paid mailers provided by petitioners.
USCIS encourages H-1B applicants to subscribe to the H-1B Cap Season email updates located on the H-1B Fiscal Year (FY) 2017 Cap Season Web page.