What breaks in year three of a mandate, not year one
10 September 2026 · OPERATIONS
Launch coverage records the first month. The interesting failures arrive later, when the schema changes and the edge cases turn out to be eleven per cent of volume.
Türkiye has operated mandatory e-invoicing for more than a decade. Not as a pilot scheme or a consultation, but as daily infrastructure at national scale, through repeated changes of format, schema and regulation.
Year one is about connection. Almost everything written about a mandate is written in year one, when the question is whether documents flow at all.
Year three is about the exceptions. A cancellation that arrives after the counterparty has already posted the invoice. A credit note whose original reference no longer resolves. A schema version that changes a field from optional to mandatory, and a queue of documents that were valid yesterday. A counterparty whose identifier was registered by a different integrator, so you can neither add it nor remove it.
None of that is exotic. It is what the middle of the system looks like once volume arrives. The reason we say we are bringing scar tissue rather than a theory is that these are the cases we have already had to answer for, at scale, with a tax authority waiting.