I recall from when we were dealing with this that the arrears are passed to the new owner, who is then liable for the unpaid levies. But our strata manager warned us that a savvy buyer might have a clause in the sale contract saying that they are not liable for unpaid levies, in which case the OC would have to sue the previous owner.
I contacted the selling agent and made sure he knew the levies were in arrears. I figured he would have some disclosure requirements and that was the best thing I could do to help our cause. I don’t know if it was the agent or the solicitor who told the buyer about the arrears – but they were paid so all is well.