Legacy coexistence: old and new AI clients on one box during migration
Real sites upgrade gradually. A compatibility listener keeps yesterday's integrations working unchanged on the classic port while everything new lands on the governed primary port, with a compiled sunset date on the old surface.
During a migration window an AI Server can serve both generations at once: modern AI Suite apps and OpenAI-compatible tools on the keyed, governed, metered primary port, and pre-v2 clients that speak the legacy local-AI wire on a dedicated compatibility listener on the classic port [1]. That listener is enabled deliberately, scoped to only the legacy surface, and carries a compiled sunset date after which it refuses to bind.
No flag-day
Because sites upgrade gradually, the compatibility listener keeps yesterday's integrations working unchanged while everything new lands on the governed primary port [1]. The upgrade migrates the legacy setting automatically on first launch when it detects the old configuration, so a brownfield site does not face a flag-day or a broken script on day one.
Scoped, and never fighting a stock install
The listener serves only the legacy surface; everything else on it returns 404 [2]. It is keyless by compatibility necessity, so treat its bind scope accordingly, keeping it to loopback unless a LAN reach is genuinely needed and then firewalling it. It never fights a real stock installation: if something else already owns the classic port, the daemon skips the compatibility listener and says so in the log rather than crashing. The primary port is unaffected, with the same governance, keys, dashboard, and metrics as every other deployment.
A sunset you can plan around
After the compiled sunset date the listener stops binding, with a clear log line, so the compatibility path has a defined end rather than an indefinite liability [1]. Repoint each legacy consumer to the primary port's OpenAI-compatible surface with a key at its own pace, and when the last one moves, disable the listener. Nothing breaks on day one, and everything is modern by the sunset.
References
- Software Tailor. "AI Server — product page." softwaretailor.com/ai-server.htm. Accessed 2026-07-22.
- Software Tailor. "AI Server documentation — API clients." softwaretailor.com/docs/ai-server/api-clients.htm. Accessed 2026-07-22.
- Microsoft. "AI Server on the Microsoft Store." apps.microsoft.com/detail/9P42956WBWCL. Accessed 2026-07-22.
Related articles
Upgrade without stranding integrations.
Old clients keep working on the classic port while new traffic lands governed. Get it on Windows from the Microsoft Store, or read the feature tour first.