The final rule which addresses the threshold adjustments effective July 1, 2020 states that the bank does need to send the change in terms (aka fund availability policy). However, the bank may make arrangements for electronic delivery or providing the change in terms in the monthly statement.
The final rule also states: In addition, a bank need not set forth the entirety of its revised funds-availability policy in its change-in-terms notice. If a bank chooses to provide the notice by sending a completely new availability disclosure, the bank must direct the customer to the changed terms in the disclosure by use of a letter or insert, or by highlighting the changed terms in the disclosure.
A change to the bank’s availability policy requires notice 30 days before the change regarding accounts; or 30 days after implementation if the change expedites funds availability.
Reference: Regulation CC: 12 CFR 229 final rule. Federal Register, July 3, 2019, page 31694.