The "new" Online help (https://online-help.sagex3.com/erp/12/en-us/Content/Home.htm) was released as part of the Sage X3 2024 R1 release.

The "Old" online help has been available, albeit no longer updated ( https://online-help.sageerpx3.com/erp/12/ ) however this will be removed when X3 2025 R1 is released (expected  May 2025).   Obviously if you have any bookmarks or links pointing to the old URLs these will cease working at this time (there is no automatic redirect).

If you still reference the "Old" help system, it is recomended you switch to the "new" help system at your earliest oppertunity