Looked at every WP.org version from 2.x to 7.106. The 512MB limit has been there since v4.5 (2015). It's a client-side JS check, filterable, and bypassable via WP-CLI. No truly "unlimited" version exists.
All-in-One WP Migration has a hard cap on upload size. Default is 512MB. The cap is enforced client-side only in the browser JavaScript, not on the server.
From version 2.x (2013) through 7.106 (current at the time of investigation), the 512MB limit has been present in all versions. The "Unlimited Extension" advertised as a paid add-on is essentially a paywall for what is already a client-side check that can be bypassed.
Three options:
wp-cli with the ai1wm restore command — bypasses the web UI entirelyUse the wp-cli approach. It's the cleanest and doesn't require modifying plugin files. The 1.88GB WPRESS file imports cleanly via:
wp ai1wm restore wpress-file.wpress --allow-root
This was the approach used for the Oscar WordPress replica deployment.