Meta’s Muse Spark series advanced rapidly with proprietary versions 1.1 through 1.3 shipping between July and early September 2026, emphasizing agentic coding, tool use, and multimodal reasoning in the Meta Model API and Muse Code. Trader sentiment for a 1.4+ release by late October now reflects low implied probability because Meta instead prioritized the October 15 open-weights launch of Muse Spark Open—an 816B-parameter MoE model with 1M context optimized for on-device inference on paired Apple M5 Ultra hardware and leading US open benchmarks. This shift, alongside the debut of the stronger Muse Wonder successor, has redirected engineering focus away from incremental proprietary Spark updates. Key upcoming catalysts include any Meta earnings commentary or developer conference hints on the next closed model, though no firm 1.4 timeline has been disclosed.