On January 30, 2024, USCIS announced the final rule for an adjusted fee schedule. The changes to fees impact many categories of applications and will go into effect on April 1, 2024. Anything postmarked on or after April 1, 2024 will be subject to the new fees. To apply under the current fee schedule, applications must be postmarked before April 1, 2024.
USCIS press release: https://www.uscis.gov/newsroom/news-releases/uscis-issues-final-rule-to-adjust-certain-immigration-and-naturalization-fees
To read the rule in its entirety (it’s long!), you can go here: https://www.federalregister.gov/documents/2024/01/31/2024-01427/us-citizenship-and-immigration-services-fee-schedule-and-changes-to-certain-other-immigration
To read the USCIS FAQ’s about the change (much shorter), you can go here: https://www.uscis.gov/forms/filing-fees/frequently-asked-questions-on-the-uscis-fee-rule
If you need to apply for a fee waiver, you can find out your eligibility by comparing your household income to the federal poverty guidelines, which are found here: https://aspe.hhs.gov/topics/poverty-economic-mobility/poverty-guidelines
