Swiss open model Apertus 1.5 adds image input and a 262K context

Project Apertus, the Swiss public AI effort, has published the full release notes and technical report for Apertus 1.5, an update to its 8B and 70B models whose weights came out in July under the Apache 2.0 licence. The new versions read images and audio as well as text (audio is still experimental), have an optional thinking mode, a context window of 262,144 tokens (four times the previous one), and better instruction-following and tool use. They are fully open: weights, training data and recipes, with data limited to permissively licensed public sources and website opt-outs respected. The team says the models still trail the best open-weight models overall, but the 8B beats similar-sized models on instruction-following and multilingual tasks, and an outside translation benchmark puts it level with GPT-OSS-20B. Swisscom, Infomaniak and other providers offer it through an API.