Arc and Zeabur both announce shutdowns, and OpenAI pulls GPT-4, GPT-3.5, o1 and o3 from the API

Two shutdowns landed in discovery today. The Browser Company is sunsetting the Arc browser on 22 December — new accounts are already closed, and Arc for macOS and Windows stops working entirely that day — pushing users to its AI-first browser Dia. Zeabur, a Railway-style deployment platform, is winding down: services pause 1 December and the platform shuts down 31 December, after two security incidents this year. And a date already on the board arrived: OpenAI removed GPT-4, GPT-3.5 Turbo, GPT-4 Turbo, o1, o3-mini and o4-mini from its API today.

Two fresh shutdowns surfaced in today’s discovery scan — a browser and a deployment platform — and one date already on the board arrived.

New on the board

The Browser Company is shutting down Arc on 22 December 2026. The company behind the much-hyped Arc browser is sunsetting it to focus on Dia, its newer AI-first browser, saying keeping a browser secure has grown harder in the age of AI. New Arc accounts already stopped on 22 October; Arc Search loses its AI features and sign-in on 23 November; 15 December is the last day to request a copy or deletion of your data; and on 22 December Arc for macOS and Windows stops working and all accounts are deactivated. If Arc is your daily browser, it’s a forced migration before year-end — Dia can import your spaces, tabs, bookmarks, passwords and extensions, as can any Chromium browser. The Browser Company’s own help-centre page is blocked to our fetcher, so every date here is confirmed against that page plus TechCrunch, 9to5Mac and Android Authority, which all agree.
Zeabur is shutting down its deployment platform on 31 December 2026. Zeabur — a Railway/Render-style platform-as-a-service for deploying apps and databases from a Git repo — is winding down after security incidents in August and October. New purchases are already halted; 1 December disables dedicated-server renewals and pauses shared-cluster services; 31 December shuts the platform down for good. The data-deletion and final-export deadlines are not yet set, so treat your own export as the real deadline. Closest like-for-like homes: Railway, Render, Fly.io, Koyeb, or self-hosted Coolify/Dokploy.

Reached today

OpenAI removes GPT-4, GPT-3.5, o1 and o3 from the API. As scheduled on OpenAI’s deprecations page and re-verified today, a large batch of older models is gone from the API as of 23 October: gpt-3.5-turbo, gpt-4 (gpt-4-0613), gpt-4-turbo, gpt-4.1-nano, the gpt-4o-2024-05-13 snapshot, o1, o1-pro, o3-mini and o4-mini, plus fine-tunes built on the retiring bases. A request that names one of these ids now returns an error — repoint to the gpt-5.6 family. This is one wave; the GPT-5 dated snapshots, o3 and o3-pro follow on 11 December.

The next three weeks, every date verified against its primary source

27 Oct — Kubernetes 1.34 end of life
30 Oct — Fitbit’s legacy Web API shutdown
31 Oct — Consul 1.22 end of life and OpenAI’s hosted Evals platform going read-only
1 Nov — Alpine 3.21 end of life, OpenSSL 3.6 end of life, and Azure Databricks Runtime 10.4 LTS
2 Nov — GitHub Actions macOS 14 runner retirement and Mullvad’s encrypted DNS shutdown
10 Nov — .NET 8 and 9 end of support, Windows 11 23H2 end of servicing and Azure Functions PowerShell 7.4
12 Nov — PostgreSQL 14 end of life

Full board with live countdowns on the calendar.