Mistral Medium 3.5 Released: 128B Dense Open-Weight Flagship Replacing Magistral, Devstral 2, Medium 3.1

Summary

Mistral shipped Medium 3.5 on April 29, 2026, consolidating chat, reasoning, and code into a single 128-billion-parameter dense model with a 256K context window, configurable per-request reasoning effort, and a from-scratch vision encoder supporting variable image sizes. Pricing is $1.50/M input and $7.50/M output tokens, the model runs on as few as four GPUs, and weights are open under a Modified MIT license. Mistral simultaneously retired three product lines: Magistral (reasoning), Devstral 2