Production BOM versions are not alternative production BOMs
During my manufacturing courses in Microsoft, when I talk about Production BOM Versions, I ever specify that they should not be used as alternative BOMs for an item valid at the same time, in particular if we use MPS/MRP. Let me explain why.
Using production BOM versions
When we create a new production BOM version in Business Central, the system asks us to specify a Version Code and, if we want, a Starting Date
Based on this date, the system calculates what is the correct BOM version to be used in the calculation when we run MPS/MRP or when we create and refresh a production order, depending on its Due Date.
In the above scenario, for example, if we create a production order having 06/01/25 as Due Date, when we run the Refresh Production Order function, we see that the system uses Production BOM Version number 30, because it's the BOM version valid at the Due Date (not on the Starting Date of the production order, as we could think).
The same happens when we run the MPS/MRP.
What happens if we don't specify the Starting Date on the Production BOM Version?
The first point we must have clear in our mind is that when we create versions, Business Central considers everytime one of them as the active version. So if we don't specify the Starting Date, which version is considered by the system?
Let's remove the dates, let's create version 20, and see what happens
If we open the Production BOM Card we can see that the Active Version is number 30.
Why? Because the calculation of the active version is based on Version Code, not on the order in which I created the versions, because in this case, the active version would have been the last one: 20.
This is the reason why I suggest not to use versions without Starting Date when we use MPS/MRP:
When we have versions without starting date, Business Central never uses the standard production BOM, but the last version it finds in the table ordered by version code
If we don't pay attention to the code we use on version, the risk is that during MPS/MRP calculation the system considers the wrong version number. Remember that the Version Code is a text, not a number, so the sorting is not the same!
For these two main reasons, having multiple BOM versions valid at the same time is not compatible with the MPS/MRP engine, but just in a scenario in which production orders are created manually by the user and in which the user selects the version to be used in every specific production order.