When the changes were announced that date-based tickets would no longer need a park reservation beginning January 9, 2024, there were some questions if there would be any changes to Park Hopping as Disney wasn't specific in the announcement.
Today, Disney has clarified this by adding the following in bold in regards to Park Hopping (and as always, this can change).
"With the updated Park Hopper experience, Guests must make a theme park reservation for the first park they plan to visit AND enter that first park prior to visiting another. At this time, a theme park reservation is not required after the first park, however, reservation requirements are subject to change. Beginning January 9, 2024, theme park reservations will no longer be required for date-based tickets. After Guests enter the first park, Guests will be able to visit the next park starting at 2:00 PM until each park’s regularly scheduled closure."