The short version: CBP has not posted the April 2027 list yet; it does so about 10 weeks before the exam. By CBP’s own rule, expect the HTSUS 2026 Basic Edition and the 2025 or 2026 edition of 19 CFR, plus the same three CBP guides as October 2026. This site’s reference viewer uses HTSUS 2026 Basic and 19 CFR revised as of April 1, 2025.
CBP’s rule
From CBP’s General CBLE Information page (last modified January 27, 2026):
- HTSUS: the Basic Edition. An April exam uses the edition of the year before; an October exam uses the current year’s.
- 19 CFR: the annual edition. An April exam uses the edition from one to two years before; an October exam uses the edition from one year before. Which one depends on when GPO prints it.
What October 2026 used
| Reference | Edition |
|---|---|
| Harmonized Tariff Schedule of the United States | 2026 Basic Edition, no supplements |
| Title 19, Code of Federal Regulations | Revised as of April 1, 2025 |
| ACE Entry Summary Instructions | Version 2.4a |
| Right to Make Entry Directive | 3530-002A |
| ACE Entry Summary Business Rules and Process Document | CBP-External 12.0 (December 2023), chapters 1 to 24 |
What this site pins, and why
| Book | Pinned edition | Why |
|---|---|---|
| HTSUS | 2026 Basic Edition (USITC, December 17, 2025) | CBP’s rule gives the prior year’s edition for an April exam. |
| 19 CFR | Revised as of April 1, 2025 | The edition October 2026 used. If CBP picks the April 1, 2026 edition, our change watch already lists every section that moved (22 sections in the parts the exam uses). |
| ACE ES, RTME, BRPD | v2.4a, 3530-002A, v12.0 | Unchanged across the last three sittings. |
When CBP posts the April 2027 list, we will check it against this page and log any change in the change log.
Paper or screen
The exam platform has electronic copies of all five references. CBP still recommends paper as a backup. Many candidates tab their paper HTSUS by section and chapter and their CFR by part. Practise both ways: the screen search behaves differently from the sample exam (see how to search fast).
Where to get the books
- HTSUS: USITC archive (free PDF by chapter).
- 19 CFR: govinfo, annual edition (free PDF).
- ACE ES Instructions, RTME Directive and ACE BRPD: free on cbp.gov.
A note on CATAIR
Some study plans list the CATAIR. CBP’s reference list names the ACE Entry Summary Business Rules and Process Document instead, so that is what this site uses.