"His significant progress is a testament to the care and aroha his caregivers have provided him."
His injuries, which included widespread bruising and a brain injury, were previously compared by former detective inspector Mike Foster to those suffered by James Whakaruru, Foster stating they were the worst he had seen in his 30-year career.
He was discharged from Starship Children's Hospital in Auckland in April 2020 to undergo rehabilitation treatment at an Auckland centre, before leaving in July.
The boy was admitted to hospital on at least one other occasion, with injuries that included broken bones.
Oranga Tamariki intervened and he was placed into the care of wider family then returned to immediate family shortly before Christmas, 2019.
A police spokesman told Hawke's Bay Today this week the investigation into the boy's injuries remained ongoing.
"Police continue to liaise with medical experts as those experts' respective reports are finalised."