Bug 880735 part D followup: flod pointed out that I changed these strings without changing the key, and since changing the key is hard I'm just going to revert them for now and do something better in a followup.

browser/locales/en-US/chrome/browser/browser.properties

@@ -160,8 +160,8 @@ pluginContinue.accesskey=C
 
 # in-page UI
 PluginClickToActivate=Activate %S.
-PluginVulnerableUpdatable=This plugin is unsafe and should be updated.
-PluginVulnerableNoUpdate=This plugin is unsafe.
+PluginVulnerableUpdatable=Thus plugin is vulnerable and should be updated.
+PluginVulnerableNoUpdate=This plugin has security vulnerabilities.
 
 # Sanitize
 # LOCALIZATION NOTE (sanitizeDialog2.everything.title): When "Time range to