Key requirements
The page includes fourth-edition guide updates in 2025, prior jurisdiction lists, return validation changes and earlier filing reminders. It is useful for tracing which rules or schema applied to a historical submission, but a past deadline or jurisdiction list is not a current-year instruction. Later developments are found in the overview and current filing guidance. When correcting an older return, distinguish its reporting-year data requirements from the schema accepted at the current submission date. Keep a version reference with the workpapers so the reasoning can be reproduced.
Official source
A concise, independent Apex Gateway guide based on the official English source, not a reproduction of the complete document. Consult the original for full conditions, exceptions and subsequent updates.
Read the official source ↗