diff --git a/app/models/dmsf_file.rb b/app/models/dmsf_file.rb
index 1faab4dd..0708c956 100644
--- a/app/models/dmsf_file.rb
+++ b/app/models/dmsf_file.rb
@@ -119,9 +119,7 @@ class DmsfFile < ApplicationRecord
   end
 
   def approval_allowed_zero_minor
-    last_revision.minor_version.zero? if Setting.plugin_redmine_dmsf['only_approval_zero_minor_version']
-
-    true
+    Setting.plugin_redmine_dmsf['only_approval_zero_minor_version'] ? last_revision.minor_version&.zero? : true
   end
 
   def last_revision
diff --git a/test/unit/dmsf_file_test.rb b/test/unit/dmsf_file_test.rb
index 8d03e730..f6fea3ba 100644
--- a/test/unit/dmsf_file_test.rb
+++ b/test/unit/dmsf_file_test.rb
@@ -304,4 +304,22 @@ class DmsfFileTest < RedmineDmsf::Test::UnitTest
     assert f
     assert_equal @jsmith.id, f.last_revision.user_id, 'Author must be updated when copying'
   end
+
+  def test_approval_allowed_zero_minor_yes
+    with_settings plugin_redmine_dmsf: { 'only_approval_zero_minor_version' => true } do
+      @file1.last_revision.minor_version = 0
+      assert @file1.approval_allowed_zero_minor
+      @file1.last_revision.minor_version = 1
+      assert_not @file1.approval_allowed_zero_minor
+    end
+  end
+
+  def test_approval_allowed_zero_minor_no
+    with_settings plugin_redmine_dmsf: { 'only_approval_zero_minor_version' => nil } do
+      @file1.last_revision.minor_version = 0
+      assert @file1.approval_allowed_zero_minor
+      @file1.last_revision.minor_version = 1
+      assert @file1.approval_allowed_zero_minor
+    end
+  end
 end