@filipg These requirements will apply to all senders with additional technical guidelines when sending to Gmail accounts for large-volume senders, meaning those who send close to or above 5K emails daily. It’s also important to note that Yahoo didn’t explicitly state their definition of bulk senders like Gmail being those who send 5K emails/day.
The guidelines being presented by Yahoo and Gmail are established sending best practices that every sender should be following today but will be more strictly enforced come February.