Decide on a cutoff date. It must be completely clear from which date invoices are fetched from the new system. This avoids duplicate invoices or invoices that fall between the systems.

Create a conversion table. If you get a new chart of accounts or production code plan, the projects create a before/after table showing which old codes become which new ones.

Notify in good time. Send the confirmed date to AIMZ a couple of weeks before the change.

Let AIMZ do the conversion. We do the switchover, so it is correct on all projects, instead of each project manager doing it themselves.

Clarify the invoice reception register. Check with the supplier of the new system that AIMZ gets access to invoices registered on receipt. Otherwise you only see the invoices once they have been processed.