diff --git a/slpkg/upgrade.py b/slpkg/upgrade.py
index 3bc28bd5..812d0e02 100644
--- a/slpkg/upgrade.py
+++ b/slpkg/upgrade.py
@@ -35,7 +35,7 @@ class Upgrade(Configs):
         """ Returns the upgradable packages. """
 
         # Returns the matched packages between two lists.
-        packages: list = list(set(self.utils.installed_package_names) & set(list(self.data.keys())))
+        packages: list = list(set(self.utils.installed_packages.keys()) & set(list(self.data.keys())))
 
         for pkg in packages:
             if self.is_package_upgradeable(pkg):