diff --git a/lib/functions.bash b/lib/functions.bash
index 01f3bf9..b087649 100644
--- a/lib/functions.bash
+++ b/lib/functions.bash
@@ -21,7 +21,7 @@ function assert_system_mode {
     >&2 echo "ERROR: development mode: $(realpath "$MIAOU_BASH_DIR")" &&
     return 3
 
-  assert_container && ! sudo test -w "$MIAOU_BASH_DIR" &&
+  assert_container && [[ $(stat -c '%U' "$MIAOU_BASH_DIR") == 'nobody' ]] &&
     >&2 echo "ERROR: hosted mode" &&
     return 4
 
diff --git a/lib/self-upgrade.bash b/lib/self-upgrade.bash
index 896410b..fc683f7 100644
--- a/lib/self-upgrade.bash
+++ b/lib/self-upgrade.bash
@@ -22,7 +22,6 @@ function self_upgrade {
 # MAIN
 
 source "$MIAOU_BASH_DIR"/lib/functions.bash
-sudo_root
 assert_system_mode
 
 current=$("$MIAOU_BASH_DIR"/bin/miaou-bash --version)
@@ -30,5 +29,7 @@ latest=$("$MIAOU_BASH_DIR"/tools/wget_semver artcode miaou/miaou-bash)
 if [[ "$current" == "$latest" ]]; then
   echo "up-to-date version: $current"
 else
+  echo "new version available: $latest"
+  sudo_root
   self_upgrade
 fi