This article reports on the identification of what is possibly the oldest complete sefer torah we have, dated c.1155-1225, at the University of Bologna. (The scroll was previously thought to date to the 17th century.) The article notes:
“I realised that the style of the writing was older than the 17th century so I consulted with other experts,” he said of the scroll, which measures 36 metres by 64 cm (39 yards by 25 inches).
He said the scroll showed many graphical features and scribal devices that were no longer used by copyists of Hebrew scripts in the 17th century.
What are these "graphical features and scribal devices" that were no longer in use by the 17th century? Are these just subtle variations in the calligraphic hand, or is it something more pronounced?
The article includes a photo, but it's not very clear and nothing jumps out at me. But I'm not a sofer(et).
(Thanks to SethJ for sharing the article.)