It supports YaRN. From the model card: "Context Length: 262,144 natively and extensible up to 1,010,000 tokens."

But, ~256k is all I can fit on my dual 32GB setup, and it gets slow as heck at 256k, anyway. I think just convincing it to chew less and do more is probably the right solution for Qwen 3.8 27B, though I guess we need some benchmarks to get the feel for how much intelligence you lose by choosing a lower reasoning level.