The "upd" likely refers to , FMOD’s most powerful iteration tool. It connects the FMOD Studio authoring tool directly to a running game build (on PC, console, or mobile).

You can connect FMOD Studio to your running game (Live Update) and tweak sounds while you play. 2. Key Update Mechanisms (The "Upd")

In the FMOD Core API, the System::update function is the "heartbeat" of the engine. It must be called once per frame to process all digital signal processing (DSP), streaming, and virtual voices.

Instead of playing a static file, FMOD uses parameters to change the music or sound effects based on what’s happening in-game (e.g., music getting more intense as health drops).