diff --git a/advisors/oa_upgradable.py b/advisors/oa_upgradable.py
index cde171fa22f74e51f5bea3b3cbe91b168e6dad71..af7abe5a740fc443ec7184af60ff331e48e480d6 100755
--- a/advisors/oa_upgradable.py
+++ b/advisors/oa_upgradable.py
@@ -130,7 +130,7 @@ def main_process(push, default, repo):
     pkg_tags = get_ver_tags(user_gitee, repo, cwd_path=default)
     print("known release tags:", pkg_tags)
 
-    if pkg_tags is None:
+    if not pkg_tags:
         return None
 
     if cur_version not in pkg_tags:
diff --git a/advisors/simple_update_robot.py b/advisors/simple_update_robot.py
index cfbe413e15d91c75fc5a4142035768bb0e24391c..8fa497d3d4527865c844209152ad11f32fc01a25 100755
--- a/advisors/simple_update_robot.py
+++ b/advisors/simple_update_robot.py
@@ -425,11 +425,14 @@ def auto_update_pkg(gt_api, u_pkg, u_branch, u_ver=None):
 
     if not u_ver:
         pkg_tags = oa_upgradable.get_ver_tags(gt_api, u_pkg)
-        if pkg_tags is None:
+        if not pkg_tags:
+            print("WARNING: Can't get {} version list, stop upgrade.".format(u_pkg))
             return
 
         ver_rec = version_recommend.VersionRecommend(pkg_tags, pkg_ver, 0)
-
+        if not ver_rec:
+            print("WARNING: Can't get {} recommend version, stop upgrade.".format(u_pkg))
+            return
 
         pkg_type = package_type.PackageType(u_pkg)
         if pkg_type.pkg_type == "core":
diff --git a/advisors/version_recommend.py b/advisors/version_recommend.py
index bd853b9c9515d3781eba5d66880c442fff7ba682..1df17e58b94dfb651906744846948d32fcbb049c 100755
--- a/advisors/version_recommend.py
+++ b/advisors/version_recommend.py
@@ -263,6 +263,7 @@ class VersionTypeXYZW(VersionType):
         version = self.get_latest_version(version_candidate, 3)
         if version:
             return self._separator.join(version)
+
         return current_version
 
     def __init__(self):
@@ -775,11 +776,15 @@ class VersionRecommend(object):
         return True
 
     def _get_latest_version(self, version_entry):
-        if self.version_type is None:
+        if not version_entry:
+            return ''
+        if not self.version_type:
             return ''
         return self.version_type.latest_version(version_entry)
 
     def _get_maintain_version(self, version_entry, current_version, pkg_type):
+        if not version_entry:
+            return ''
         if self.version_type is None:
             return ''
         return self.version_type.maintain_version(version_entry, current_version, pkg_type)