I have a saved webmap containing layers pointing at an ArcGIS Server which is now switched off. I need to update webmap, changing the layer URLs to a new ArcGIS Server URL. Layers were added straight to the map using Add Layer From Web. I need the old webmap so I retain styling and popup configuration. My web map ID is also referenced in a JS app. Apparently I can edit the URLs for layers and apps, but not maps. Why? Anyone know a way to edit the layer URLs?
"URL (Apps and ArcGIS Server layers only)—Changing the URL of an ArcGIS Server layer is only recommended when you move the service to a different server. If you've changed the service—for example, added or removed layers—you should add the service as a new item. Any map that uses the moved layer will appear broken because it references the old URL. To fix the map, delete the layer, add it again with the new URL reference, and save the map. Any layer properties you saved to the item are still available. If you edit the URL of a changed service, the map may not display correctly, even after you readd the layer. You cannot edit the URL of a hosted feature or tile layer.