From version X-Train 3.4.19.4 there is a way to monitor Skills to ensure the material is up to date.

Options to monitor skills

• Material Changed  - column to be set when the related Material (e.g. SOP version) is reset to draft, or otherwise state changed.

• Material New Version - column to be set when the related new Material version is published.

• Material Missing - column to be set when the related Material is archived.

Skills > Published