This scenario requires a two-part solution: one for migrating existing historical documents and another for creating new documents post-go-live.

1. For existing legacy documents that need to be entered into SAP Business One (e.g., open A/R invoices), a manual numbering series is used. This allows the user to enter the exact, original document number from the legacy system, thus preserving the historical numbering without alteration.

2. For new documents created after the system goes live, a new automatic numbering series should be defined. The "Next Number" for this series must be set to the number immediately following the last used number in the legacy system. This ensures a seamless and continuous numbering sequence with no breaks.

C. Use the primary series with a prefix for the legacy numbers: This is incorrect because adding a prefix changes the document number, which violates the requirement to continue the exact legacy numbers.

D. Use the primary series and change the starting number: While technically possible, creating a new, dedicated series (Option B) is better practice than altering the default primary series, which may be needed for other standard purposes.

1. SAP Business One 10.0 Help Portal; Document Title: Document Numbering - Setup Window.

Reference Details: In the section describing the fields for setting up document numbering

the documentation implicitly supports the use of manual series for entering specific numbers and setting the "Next No." field for automatic series to control the sequence. This directly supports options A and B as the standard mechanism for this requirement.

2. SAP Business One TB120010 Course Material; Unit: System Initialization.

Reference Details: The "Document Numbering" topic within this unit explains the distinction between automatic and manual series. It outlines the best practice for data migration

which involves creating a manual series to import historical documents with their original numbers. It also details how to set up a new automatic series to continue a specific numbering sequence for ongoing operations

aligning perfectly with answers A and B.