Scandalous to me that although the software is entirely discredited, and although this has been known for years now, only 72 people have been cleared.
It's also hugely embarrassing to the justice system of course. In a way it's the fault of societies near blind assumption that expert=truthful. The Fujitsu people need to go to jail because they repeatedly assured the courts that the software couldn't be at fault even though they had a bug tracker full of loss-of-transactionality bugs. And the legal system just said, well, they're the experts, so if they said it, it's true.
They also had incredibly awkward bugs like "the touch screen hardware we deployed had a bad manufacturing batch that caused a subset to start submitting random button presses 12 months after deployment". It took them a while to realize that the actions weren't genuinely being made by the post masters, etc.
And yeah, iirc they lied to the court. Courts are supposed to anticipate this of course, but unfortunately defense teams near universally didn't push them on this or try to uncover their lies. Like I said, our culture has a severe problem with assuming experts are always honest and trustworthy. It's a totally flawed assumption and it resulted in hundreds of lives being destroyed in this case, but literally, nobody in the legal system including the defense really tried to probe whether the software really did work as the authors said it did. They just accepted the assurances made that it was perfect.
The set of people convicted for stealing from the Post Office could include someone who was caught red-handed with an open till, wearing a stripey shirt and a Zorro mask and carrying a large sack with SWAG written on it in bold letters. Obviously this hypothetical thief shouldn't be acquitted with all the innocent people.
IANAL
Since 2010 there have been large cuts to the police, the courts, the pay of barristers and to legal aid [2]. The result is a massive backlog in cases and covid came on top of that. So it currently takes years to get anything done in the British legal system. There is a lot more broken that just this particular piece of software.
[1] I don't know if the response to these appeals is the duty of the Crown Prosecution Service or the Post Office. The costs will ultimately be borne by the public purse in either case, the PO is financially obliterated by it's liabilities.
[2] The system for paying the legal costs of individuals in court in the UK. Very little of it is left now.
Edit: I don't think anyone is still prison for these convictions. Most sentences were for less than three years and the whole process has been dragging on for a long time.
Again, leaving innocent citizens with a record cannot be excused on any level after the problem has become known.