The best way is to manage dual configurations as a controlled, time-bounded coexistence model with explicit effectivity, traceability, and governed change control across engineering, planning, production, quality, and service records.
In practice, that means keeping both configurations formally valid for a defined period, rather than letting the transition happen through tribal knowledge, spreadsheet exceptions, or informal shop floor decisions. Each configuration should have clearly approved structures, routings, work instructions, inspection requirements, and disposition rules tied to the correct serial, lot, date range, customer requirement, or unit effectivity as applicable.
What usually works best
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Define a single authoritative change decision with formal approval and implementation criteria.
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Use explicit effectivity logic so teams know exactly when the legacy design applies and when the new design applies.
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Maintain separate but linked records for BOMs, routings, specifications, inspection plans, and work instructions where the process actually differs.
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Preserve as-built and as-maintained traceability so you can prove which configuration was used for each unit, order, or serial number.
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Control inventory exposure, including WIP, stocked components, supplier-held material, tooling, and service spares.
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Synchronize cutover points across PLM, ERP, MES, QMS, and document control. If those systems are not aligned, dual configuration control breaks down quickly.
If you need a short answer, it is this: treat the transition as an operational governance problem, not just an engineering revision problem.
Why companies struggle
Most failures happen because the design release changes faster than the execution systems and physical inventory can absorb. Engineering may be ready for the new configuration while purchasing, suppliers, planners, operators, inspectors, and field support are still working against the old one. In regulated and long lifecycle environments, that mismatch creates documentation errors, wrong-part installs, inspection escapes, rework, and weak traceability.
It is also common for one system to carry the new revision while another still drives the old routing or inspection plan. That is a brownfield integration problem, not a minor inconvenience. If PLM, ERP, MES, and QMS are loosely connected or manually synchronized, dual configuration management depends heavily on process discipline and validation of each handoff.
Key controls to put in place
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Effectivity control: Define exactly what determines applicability, such as serial number, work order range, customer program, date, or lot.
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Configuration-specific execution records: Make sure operators and inspectors see only the approved instructions for the unit they are building or servicing.
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Inventory segregation: Prevent legacy and new components from being mixed where interchangeability is restricted or undocumented.
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Deviation and exception handling: Use formal disposition paths for units caught mid-transition, especially for WIP and supplier returns.
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Traceability: Record which parts, documents, process parameters, inspections, and approvals were actually used.
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Change freeze windows where needed: For high-risk transitions, temporary release discipline can reduce overlapping revisions and confusion.
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Retirement criteria for the old configuration: Define when the legacy configuration is no longer buildable, supportable, or purchasable.
System strategy in brownfield environments
Do not assume the best answer is replacing your existing stack. In many regulated plants, full replacement during a live design transition is high risk and often fails because of qualification burden, validation cost, downtime risk, integration complexity, and long equipment and program lifecycles.
A more reliable approach is usually to strengthen coexistence between systems you already have. That may include improving revision handoffs from PLM to ERP, tightening MES enforcement of effectivity, adding document governance around work instructions, and ensuring QMS records can reference both configurations without ambiguity. This is less elegant than a clean-sheet architecture, but often more realistic.
If your systems cannot enforce configuration effectivity directly, compensate with controlled procedural checks, but be clear about the tradeoff: manual controls can work, yet they are harder to sustain, harder to audit internally, and more vulnerable to training gaps and local workarounds.
Tradeoffs to expect
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Longer coexistence windows reduce disruption but increase complexity, inventory exposure, and documentation burden.
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Fast cutovers reduce duplication but raise scrap, shortage, and downtime risk if suppliers and internal systems are not ready.
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Strict system enforcement improves control but may require integration work, validation effort, and temporary throughput loss during rollout.
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Manual bridging controls are faster to deploy but weaker over time and more dependent on training and supervision.
So the best method is not the most automated or the fastest. It is the one that preserves configuration integrity with the least operational risk, given your data quality, integration maturity, validation constraints, and production reality.
Practical rule of thumb
If you cannot answer, for any shipped or serviced unit, which configuration was authorized, which one was built, which documents were in effect, and what exceptions were approved, then your dual configuration process is not under adequate control.