looking for the details while updating retention.ms and below is the scenario

1. created topic t1 with retention.ms 6 hrs
2. produces 10 messages
3. After 2 hrs, modified retention.ms to 24 hrs.
4. produces 10 messages

Question: does this change application to earlier messages(10 messages produced 2 hrs earlier-step-2)? OR it is applicable to newly produced messages only(messages of step 4)?