“The breakthrough seems to have come from Mochizuki explaining his theory in person. He refuses to travel abroad, only speaking via Skype at the Oxford meeting, which had made it harder for mathematicians outside Japan to get to grips with his work.”

Mathematicians finally starting to understand epic ABC proof | New Scientist

It’s interesting that Skype is mentioned without explanation but it also shows the limitations of the technology without training. We still have progress to make.