SMT4 is a bit of a surprise here. Obviously POWER uses it well but this feels like new territory for ARM designs.
Edit: Apparently the Cortex A65AE ("AE" = automotive enhanced) was released last year and was the first ARM core with multithreading.
Having multiple threads by having multiple cores is a different thing.
[1] It's actually more complicated than that, with register aliasing etc, but it's a decent conceptual model.