This is somewhat old news, but was not previously reported. On March 14, 2024, the Fifth Circuit voted 10-5 not to rehear Republican National Committee v Wetzel, 24-60395. The original panel had voted that Mississippi was breaking federal law when it allowed mailed ballots to be counted even though they had not been received in the elections office by election day. The original panel said the 19th century federal law that tells the states they must hold congressional elections on the first Tuesday after the first Monday of November means that all ballots must be received by election day.Here is the order denying rehearing. The Fifth Circuit decision is at odds with virtually every other lawsuit on this subject.
It is extremely likely that case will be appealed to the U.S. Supreme Court.