Meta's rapid four-week release cadence on the Muse Spark large language model series, with 1.3 shipping September 2 after 1.2 in early August, drives trader expectations for Muse Spark 1.4+ arriving in mid-to-late October. The model family focuses on gains in agentic workflows, coding benchmarks, and multimodal reasoning through expanded training on long-horizon tasks, while delivering efficiency improvements like reduced tool calls. Competitive pressure from frontier labs and Meta Superintelligence Labs' roadmap—including open-weights versions and larger models—add momentum, though no official 1.4 announcements have surfaced since the 1.3 launch. Polymarket traders currently assign roughly 88% implied probability to a release by October 31, reflecting historical patterns and Meta's push into developer APIs and Muse Code tooling.