diff --git a/data/helpers.d/logging b/data/helpers.d/logging
index 582d48428..8464a414f 100644
--- a/data/helpers.d/logging
+++ b/data/helpers.d/logging
@@ -285,6 +285,16 @@ ynh_script_progression () {
 	set -x
 }
 
+# Return data to the Yunohost core for later processing
+# (to be used by special hooks like app config panel and core diagnosis)
+#
+# usage: ynh_return somedata
+#
+# Requires YunoHost version 3.6.0 or higher.
+ynh_return () {
+    echo "$1" >> "$YNH_STDRETURN"
+}
+
 # Debugger for app packagers
 #
 # usage: ynh_debug [--message=message] [--trace=1/0]
diff --git a/src/yunohost/app.py b/src/yunohost/app.py
index b98dec1bb..85ac9796c 100644
--- a/src/yunohost/app.py
+++ b/src/yunohost/app.py
@@ -1603,31 +1603,12 @@ def app_config_show_panel(app):
         "YNH_APP_INSTANCE_NAME": app,
         "YNH_APP_INSTANCE_NUMBER": str(app_instance_nb),
     }
-    parsed_values = {}
 
-    # I need to parse stdout to communicate between scripts because I can't
-    # read the child environment :( (that would simplify things so much)
-    # after hours of research this is apparently quite a standard way, another
-    # option would be to add an explicite pipe or a named pipe for that
-    # a third option would be to write in a temporary file but I don't like
-    # that because that could expose sensitive data
-    def parse_stdout(line):
-        line = line.rstrip()
-        logger.info(line)
-
-        if line.strip().startswith("YNH_CONFIG_") and "=" in line:
-            # XXX error handling?
-            # XXX this might not work for multilines stuff :( (but echo without
-            # formatting should do it no?)
-            key, value = line.strip().split("=", 1)
-            logger.debug("config script declared: %s -> %s", key, value)
-            parsed_values[key] = value
-
-    return_code = hook_exec(config_script,
-                            args=["show"],
-                            env=env,
-                            stdout_callback=parse_stdout,
-                            )[0]
+    return_code, parsed_values = hook_exec(config_script,
+                                args=["show"],
+                                env=env,
+                                return_format="plain_dict"
+                                )
 
     if return_code != 0:
         raise Exception("script/config show return value code: %s (considered as an error)", return_code)
diff --git a/src/yunohost/hook.py b/src/yunohost/hook.py
index 42807fdf7..67e77f033 100644
--- a/src/yunohost/hook.py
+++ b/src/yunohost/hook.py
@@ -297,8 +297,7 @@ def hook_callback(action, hooks=[], args=None, no_trace=False, chdir=None,
 
 
 def hook_exec(path, args=None, raise_on_error=False, no_trace=False,
-              chdir=None, env=None, user="root", stdout_callback=None,
-              stderr_callback=None):
+              chdir=None, env=None, user="root", return_format="json"):
     """
     Execute hook from a file with arguments
 
@@ -372,8 +371,8 @@ def hook_exec(path, args=None, raise_on_error=False, no_trace=False,
 
     # Define output callbacks and call command
     callbacks = (
-        stdout_callback if stdout_callback else lambda l: logger.debug(l.rstrip()+"\r"),
-        stderr_callback if stderr_callback else lambda l: logger.warning(l.rstrip()),
+        lambda l: logger.debug(l.rstrip()+"\r"),
+        lambda l: logger.warning(l.rstrip()),
     )
 
     if stdinfo:
@@ -401,19 +400,31 @@ def hook_exec(path, args=None, raise_on_error=False, no_trace=False,
     try:
         with open(stdreturn, 'r') as f:
             raw_content = f.read()
-        if raw_content != '':
-            returnjson = read_json(stdreturn)
+        returncontent = {}
+
+        if return_format == "json":
+            if raw_content != '':
+                try:
+                    returncontent = read_json(stdreturn)
+                except Exception as e:
+                    raise YunohostError('hook_json_return_error',
+                                        path=path, msg=str(e),
+                                        raw_content=raw_content)
+
+        elif return_format == "plain_dict":
+            for line in raw_content.split("\n"):
+                if "=" in line:
+                    key, value = line.strip().split("=", 1)
+                    returncontent[key] = value
+
         else:
-            returnjson = {}
-    except Exception as e:
-        raise YunohostError('hook_json_return_error', path=path, msg=str(e),
-                            raw_content=raw_content)
+            raise YunohostError("Excepted value for return_format is either 'json' or 'plain_dict', got '%s'" % return_format)
     finally:
         stdreturndir = os.path.split(stdreturn)[0]
         os.remove(stdreturn)
         os.rmdir(stdreturndir)
 
-    return returncode, returnjson
+    return returncode, returncontent
 
 
 def _extract_filename_parts(filename):