It was the Cypher System we switched to. Oddly, I wouldn’t recommend it and would much prefer to have stuck to a crunchier system, but the idea was to compromise with some of my players who prefer to focus on story, and enable me to run the game without extensive conversion work. (I got to the point where I could convert on the fly and use the 4e stat blocks as I went.)
Still wish we’d finished in 4e but the combats... took... too... long...
(We were very lucky to get our campaign in under the lockdown wire as we haven’t gamed in person since.)