AI Model Release Tracker - Timeline of Major AI Models from 2022-2026

Mistral Medium 3.5 vs o4-mini-high

Mistral
Mistral Medium 3.5
OpenAI
o4-mini-high
Overview
CompanyMistralOpenAI
Release dateApr 29 2026Apr 16 2025
Model type
Open sourceYesNo
Specifications
Parameters
128B
Context window
256k
Benchmarks
Coding
SWE-Bench Verified
77.6%
Timeline
Release gapo4-mini-high shipped 378 days before Mistral Medium 3.5

Which is better: Mistral Medium 3.5 or o4-mini-high?

Mistral Medium 3.5 and o4-mini-high don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. o4-mini-high shipped 378 days before Mistral Medium 3.5, so benchmark comparisons should account for the intervening progress.

Mistral Medium 3.5 is an open-source / open-weight model; o4-mini-high is proprietary.

Direct benchmark comparisons are unavailable — Mistral Medium 3.5 and o4-mini-high don't publish scores on any of the same benchmarks.

Frequently asked questions

When was Mistral Medium 3.5 released?
Mistral Medium 3.5 was released by Mistral on Apr 29 2026.
When was o4-mini-high released?
o4-mini-high was released by OpenAI on Apr 16 2025.
Is Mistral Medium 3.5 or o4-mini-high open source?
Mistral Medium 3.5 is an open-source / open-weight model released by Mistral. o4-mini-high is a proprietary model released by OpenAI.

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