Proton partners with Apertus, Switzerland's sovereign AI model | Proton

Proton announced a partnership with Apertus, Switzerland's sovereign AI model, according to a September 23, 2026 post in the Privacy Guides Community. The announcement drew a community response asking whether Proton would now release the source code for its Calendar app. Apertus was previously launched as a public, open-source AI model built for privacy, and Proton's own Lumo AI product has faced community scrutiny over its open-source claims.

Privacy Guides Community Proton partners with Apertus, Switzerland's sovereign AI model | Proton General News article Abdalonymus September 23, 2026, 4:24am 1 1 Like not-wittingly September 23, 2026, 5:11am 2 Awesome. Can they release the Calendar app source code now. Related topics Topic Replies Views Activity Switzerland Launches Apertus: A Public, Open-Source AI Model Built for Privacy News article , software 15 1750 September 6, 2025 Introducing Lumo, the AI where every conversation is confidential | Proton General article 184 16131 July 2, 2026 Proton is moving most of its physical infrastructure out of Switzerland General article 87 12144 December 13, 2025 Proton markets Lumo as "open source," but support calls it a "long-term intention, not the instantaneous state" General 84 6865 April 1, 2026 Proton Released A New Privacy Product? | This Week in Privacy 11 Jul. 25, 2025 Livestreams 11 1799 July 26, 2025