The documentation for "Assign layer IDs " instructs the administrator on how to set up static layer IDs:
https://pro.arcgis.com/en/pro-app/latest/help/sharing/overview/assign-layer-ids.htm
Unfortunately, even when that feature is enabled, this behavior does not extend to the OGC "WMS" layer IDs. These numeric layer IDs continue to be automatically assigned based on each layer's order in the group, so they sometimes change when new layers are inserted above them in the stack order. This forces all WMS users to update their client code and websites to use the new numeric layer ID after an update is published, which is undesirable. For this reason, it would be really great if the same static, unique layer IDs were used by all services that ArcGIS publishes, including the WMS service. I am one of the end users of the WMS, not an administrator myself.
To provide a specific example, see the following WMS GetCapabilities XML snippet from an ArcGIS WMS service:
<Layer queryable="1">
<Name>25</Name>
<Title>State Land Use Districts</Title>
As you can see, ArcGIS assigns a layer ID (in the "Name" field) of "25". In this example, the Name value has changed a number of times since its original publication from 17 to 22, to 23, back to 22, then to 23, 24, and now 25, etc. as layers have been added or removed above it in its group. If this layer ID was static and stayed the same between updates, as is true for other ArcGIS services, myself and other users would not need to modify their client code and websites to point at the new layer ID when this happens.
Many thanks for your consideration in implementing this enhancement request.
