Try pkexec

Author: probonopd

progress.vala

@@ -103,8 +103,9 @@ public class ProgressWindow : Window {
  int extra_args = 0;
 
  string[] spawn_args = new string[8 + files_to_be_updated.length + extra_args];
- spawn_args[0] = "appimageupdate";
- spawn_args[1] = this.file_name;
+ spawn_args[0] = "pkexec";
+ spawn_args[1] = "appimageupdate";
+ spawn_args[2] = this.file_name;
 
  string[] spawn_env = Environ.get ();
  int standard_error;