"These protocol changes are an incremental step, and we are continuing to work on improvements to Signal’s metadata resistance. In particular, additional resist

"These protocol changes are an incremental step, and we are continuing to work on improvements to Signal’s metadata resistance. In particular, additional resistance to traffic correlation via timing attacks and IP addresses are areas of ongoing development." It won't prevent correlation attacks, but it does make metadata attacks in general harder and less confident. An improvement is an improvement even if it doesn't completely solve a problem.