ISB ~ Acts 28 v31

unhindered:The preaching of Paul in Rome is a preliminary fulfillment of Jesus’ mandate to witness to the “end of the earth” (1:8). Scholars generally hold that Luke has left this conclusion open-ended to show that the Church’s mission to the world, far from drawing to a close, has only just begun. Also, the fact that Luke’s narrative reaches a climax with Paul still shackled as a prisoner may suggest that the Book of Acts was written about this time, around A.D. 63.

The inference is not conclusive in itself, but, combined with other factors, it leads to a compelling case for dating Acts in the early 60s. See introduction to Acts: Date.