AES Replacing ECS — What Changed for EU Exporters
On 31 October 2024, the EU's export customs system underwent its most significant transformation in over a decade. The Automated Export System (AES) -- specifically its second phase, often called AES PLUS or ECS Phase 2 — replaced the legacy Export Control System (ECS) in multiple member states. The most visible change for exporters: the CC599C message now replaces IE599 as the official confirmation of export. This article explains what changed, what stayed the same, and what every exporter needs to know.
Background: From ECS to AES
The EU's export customs IT infrastructure has evolved in phases:
- ECS (Export Control System) — original deployment (2007-2009): The first electronic export system across EU member states. Introduced standardized electronic messaging for export declarations, including IE515 (export declaration), IE528 (acceptance and MRN allocation), IE529 (release for export), and IE599 (confirmation of exit). This system used “IE” (Information Exchange) message prefixes.
- AES Phase 1 (2020-2023): Incremental updates to the ECS system, aligning it with the Union Customs Code (Regulation (EU) No 952/2013) which replaced the Community Customs Code. Data model updates but no fundamental architecture change.
- AES Phase 2 / AES PLUS (from 31.10.2024): A comprehensive rebuild of the export system. New message formats (CC-prefix replacing IE-prefix), expanded data requirements, improved inter-system communication, and alignment with the UCC Data Model. This is the current system.
The legal foundation for this transition is Art. 6(1) of Regulation (EU) No 952/2013 (UCC), which mandates the use of electronic data processing techniques for all customs decisions and formalities, and the UCC Work Programme which set the implementation timeline.
What Is AES PLUS?
AES PLUS is the operational name for the updated Automated Export System deployed since 31 October 2024. Key characteristics:
- New message standard: All messages use the “CC” (Customs-to-Customs) prefix instead of “IE”. For example: CC515C replaces IE515, CC518C replaces IE518, CC599C replaces IE599.
- Enhanced data model: More structured data fields, mandatory elements aligned with the UCC Annex B data requirements, and standardized code lists.
- Improved inter-member-state communication: Better handling of cross-border exports (indirect export) where the customs office of export is in a different member state than the customs office of exit.
- Integration with ICS2: Alignment with the Import Control System 2 for a more coherent customs IT architecture.
For national systems, this meant significant upgrades. In Poland, the PUESC (Platforma Usług Elektronicznych Skarbowo-Celnych) system was updated to handle AES PLUS messages. In Germany, the ATLAS system received corresponding updates.
CC599C vs IE599 — What Actually Changed?
For exporters, the most important message in the export chain is the confirmation of exit. Here is how the old and new versions compare:
| Attribute | IE599 (old ECS) | CC599C (AES PLUS) |
|---|---|---|
| System | ECS (Export Control System) | AES PLUS |
| Active until/from | Until 31.10.2024 | From 31.10.2024 |
| Function | Confirms goods left the EU | Confirms goods left the EU |
| Legal force | Full proof of export | Full proof of export |
| Accepted for 0% VAT | Yes | Yes |
| Data format | XML (IE schema) | XML (CC schema, expanded) |
| Generated by | Customs office of export | Customs office of export |
The bottom line: CC599C and IE599 have identical legal force. Both serve as proof of export accepted by tax authorities for the 0% VAT rate. The change is in the technical format and the underlying system, not in the legal or practical significance for the exporter. More details in our VAT 0% and CC599C article.
New Message Formats in AES PLUS
The transition affected the entire export message chain. Here are the key messages relevant to exporters:
| Function | Old (ECS) | New (AES PLUS) |
|---|---|---|
| Export declaration | IE515 | CC515C |
| Acceptance / MRN allocation | IE528 | CC528C |
| Release for export | IE529 | CC529C |
| Exit results (office to office) | IE518 | CC518C |
| Confirmation of exit (to declarant) | IE599 | CC599C |
| Amendment request | IE513 | CC513C |
| Invalidation request | IE514 | CC514C |
For a practical understanding of how IE529 and IE599 differ in the export flow, see our detailed comparison: IE529 vs IE599 differences.
Country Rollout Timeline
The AES PLUS rollout has been staggered across EU member states. Each country had to update its national customs IT system to handle the new message formats and data requirements.
| Country | AES PLUS Go-Live | Status (March 2026) |
|---|---|---|
| Poland | 31 October 2024 | Fully operational |
| Germany | Q1 2025 | Fully operational |
| Netherlands | Q1 2025 | Fully operational |
| Belgium | Q2 2025 | Fully operational |
| France | Q2 2025 | Fully operational |
| Italy | Q3 2025 | Operational, minor issues |
| Other EU states | Q3-Q4 2025 | Mostly operational |
Impact on MRN Closure
The AES transition has had a mixed impact on MRN closure:
Positive changes
- Better cross-border communication: The new CC518C message (replacing IE518) carries more structured data, reducing the incidence of inter-office communication failures between the customs office of exit and the customs office of export.
- Improved data matching: The enhanced data model in AES PLUS provides more data points for port systems to match export declarations to vessel manifests, potentially improving automatic matching rates.
- Standardized error handling: The new system provides clearer error messages and status updates, making it easier to diagnose and resolve MRN closure issues.
Challenges encountered
- Transition-period delays: During the initial months after go-live, some member states experienced processing delays as systems stabilized. These have largely been resolved.
- Port system updates required: Port community systems (Portbase, ZAPP/EMP, APCS, BHT) needed to update their interfaces to handle the new message formats. Some ports adapted faster than others.
- Customs agent software updates: Agents using legacy software needed upgrades to file declarations in the new format, occasionally causing delays during the transition window.
As of March 2026, the transition is largely complete and MRN closure timelines have normalized. See our MRN closure timeline article for current processing times per port.
What Exporters Need to Do
For most exporters, the practical implications are limited:
- Accept CC599C alongside IE599: Update your internal processes and accounting systems to recognize CC599C as equivalent to IE599. Both are valid proof of export.
- Inform your accountant: Ensure your accountant or tax advisor understands that CC599C has the same legal force as IE599 for VAT purposes.
- Verify your customs agent is updated: Confirm that your customs agent or broker is filing declarations through the AES PLUS system and can handle the new message formats.
- Keep both types: If you have exports spanning the transition period, retain both IE599 (for pre-October 2024 exports) and CC599C (for newer exports) in your records.
FAQ — AES Replacing ECS
Is CC599C the same as IE599?
Functionally, yes. CC599C serves the same purpose as IE599 — confirming that goods have physically left EU territory. The difference is the system that generates it: CC599C comes from AES PLUS, while IE599 came from the older ECS system. Both have identical legal force as proof of export for VAT purposes. There is no need to convert existing IE599 messages to CC599C.
When did the transition from ECS to AES happen?
The AES PLUS system went live on 31 October 2024 in Poland and several other EU member states. However, the rollout has been staggered across the EU — some countries transitioned in late 2024, others are following in 2025. During the transition period, both systems may be encountered depending on which member state processes the export declaration.
Do I need to do anything differently as an exporter because of AES?
For most exporters, the transition is largely transparent. Your customs agent files the export declaration in the new system, and you receive CC599C instead of IE599. The core information content is the same. The main practical difference is in message numbering (CC-prefix instead of IE-prefix) and slightly expanded data fields. Your accounting and VAT processes do not need to change.
Does AES affect MRN closure timelines?
The AES transition itself does not significantly change MRN closure timelines. The port community systems (Portbase, ZAPP/EMP, APCS, BHT) continue to operate as before and interface with the new AES PLUS. Some initial teething issues were reported in late 2024, but these have largely been resolved. Standard closure times remain 2–8 hours depending on the port.
What happens to my old IE599 messages? Are they still valid?
Yes, absolutely. IE599 messages issued before the AES transition remain fully valid as proof of export. There is no expiry date on their validity, and tax authorities continue to accept them for historical exports. You should retain them in your records for the standard statute of limitations period (typically 5 years).
Legal basis: Art. 6(1) and Art. 269-274 of Regulation (EU) No 952/2013 (Union Customs Code); UCC Work Programme established by Commission Implementing Decision (EU) 2019/2151; Art. 329-336 of Commission Implementing Regulation (EU) 2015/2447. Rollout dates based on European Commission published schedules and national customs authority announcements. This article is for informational purposes and does not constitute legal advice. Updated: March 2026.
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