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Assigned when it is an input attribute on a workflow step (even if marked as always read-only) and that step is saved (any action except Cancel).
Since the field is not assigned until it is saved, we recommend that you make it a hidden field on the first step of a workflow. Once on the second step, it can then be displayed.
Once the auto number is generated, it cannot be changed, even if it is listed as an input attribute.
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Limitations
The default value settings are ignored by the Autonumber data type.
The Autonumber is not generated when entity instances are created during an upload.
Activity ID and Unique ID Autonumbers do NOT respect numbers assigned manually or via upload so if a number is assigned manually or via upload, it may be duplicated when the Automber algorithm assigns a number.
Autonumbers CANNOT be assigned during nightly automation as it will create inadvertent duplicates. See
.Jira Legacy server System JIRA serverId 80a5de98-58ff-3b59-a4bd-e013083b8a1d key LB-2611
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