v1.12.0 This endpoint still works as before but is deprecated. Use config instead.
Post the full contents of the configuration, in the same format as returned by the corresponding GET request. When posting the configuration succeeds, the posted configuration is immediately applied, except for changes that require a restart. Query rest-config-insync to check if a restart is required.
This endpoint is the main point to control Syncthing, even if the change only concerns a very small part of the config: The usual workflow is to get the config, modify the needed parts and post it again.