Hello - I have a Field Maps mobile app that is integrated with Survey123 forms that populate a hosted feature layer that contains related layers and tables. Users use the app to collect information on shoreline structures, marsh areas, transect points, project limits, etc. for monitoring shoreline protection projects.The users take the Field Maps app into the field and create point, line, and polygon features with the app based on the type of feature collected and then repeatedly monitor these structures and add data (using the Survey123 forms via buttons in Field Maps) after each inspection. The information for these features is located on layers that has related layers and related tables. For example, a shoreline structure is related to a parent Monitoring Site polygon. That structure feature also has a related table that collects repeated data collections overtime for that specific structure. We have outside partners that have collected data from sites using RTK to enhance location accuracy. We want to import these external RTK-collected features (not collected with Field Maps) into our hosted feature layer in ArcGIS Online so they appear in Field Maps for user and can be analyzed with the rest of the data in Field Maps. How would I add this data to be usable in the Field Maps app for other users? What format would be best for the data to be received from the people who want to add their RTK features to the dataset? Would each feature need to be added to each specific layer and related table as appropriate in ArcGIS Online? I believe adding the data to ArcGIS Pro, appending, and then publishing the updates would be required. But will this cause the ID of my hosted feature layer to change. This serves a Map used in Field Maps that has over a year of formats and design. I don't want to have to recreate it since it integrates Survey123 buttons and lots of custom stuff. Would the ID change? Maybe this is not an issue? I believe I could overwrite the existing hosted feature layer when publishing updates to keep the ID, but that is scary since there are 2 years of design work for the map and 2 years of data collection if something goes wrong. I don't want to mess it all up. Are there any other options? Can Python Scripting be used to update the hosted feature layer with the new RTK data? Thank you for any input and please let me know if I have left any information out to help with guidance!