Apertus 1.5 report opens its multimodal training and evaluation stack
Swiss AI published the Apertus 1.5 technical report, documenting continued pretraining, early-fusion image and audio tokenization, optional thinking, tool use and a 262,144-token context for its Apache-2.0 8B and 70B models. The weights themselves were released on 24 July; the new October event is the reproducibility and evaluation record.
Why it matters: The report makes a large multimodal model's data, training stages, values and evaluation choices unusually inspectable. It enables replication and audit work without mislabeling an older checkpoint as a new release, but openness does not establish…