Overwriting a feature service does not update the symbology in a web map in ArcMap

Description

When updating the symbology of a feature service and overwriting the service using ArcMap, updates made to the symbology are not reflected in a web map after republishing to ArcGIS Online.

Cause

This is expected behavior when overwriting a feature service in a web map that already has symbology applied and saved. By design, when the feature service is overwritten, the symbology saved previously in the web map is maintained because overwriting the service only updates the feature service and not the JSON file of the web map, which stores all properties of the saved web map. The properties of the web map stored in the JSON file include web map layers, labels, pop-up configurations, and symbology. When overwriting a feature service in the web map, the updated symbology is only reflected in the web map if no symbology is configured and saved in the ArcGIS Online web map viewer prior to overwriting the feature service.

Solution or Workaround

Warning:   
The following workflow may cause any pop-ups in the feature service layer to be deleted.

As a workaround, follow the steps provided below:

1. Remove the feature service layer from the web map. Refer to ArcGIS Online: Organize layers (Map Viewer Classic) for instructions.
2. Update the symbology of the layer in ArcMap. Refer to ArcMap: Modifying symbols for feature layers for instructions.
3. Republish the layer as a feature service to ArcGIS Online. Refer to ArcMap: Publish a map service form ArcMap for instructions.
4. Add the feature service to the web map.
5. Save the web map, and the updated symbology of the feature service is reflected.