In a classic BPM model, you can have multiple inbound sequence flow into steps that are not gateways. The "converging behavior" of these sequence flows is defined by the join type (Or, And, Complex, Unsynchronized Or) configured in the Join properties panel for that step. In Dynamic Business Orchestrator, only gateways can have multiple inbound sequence flow, therefore it is necessary for the migration utility to insert a gateway to replace the multiple inbound sequence flow. Insertion of Gateways will be one of the most obvious changes to your model as the migration utility inserts gateways in the diagram to preserve the overall look. The resulting gateway will dramatically improve the readability of the model notation by better illustrating what the converging behavior of the sequence flow should be.

For example, if your step was governed by an "OR" Join, the migration utility will insert an Inclusive gateway and reassign the sequence flow from the source steps to the gateway and then from the gateway to the target step. The following image is an example of how this looks in a classic and the migrated Dynamic Business Orchestrator model.

Depending on the type of join, the following gateways are inserted for multiple inbound sequence flow: