         }
 
         // check if the app has been used enough times
-        var useCount = userDefaultsObject?.integerForKey(keyForArmchairKeyType(ArmchairKey.UseCount))
+        let useCount = userDefaultsObject?.integerForKey(keyForArmchairKeyType(ArmchairKey.UseCount))
         if let count = useCount {
             if UInt(count) <= usesUntilPrompt {
                 return false

        }
#elseif os(OSX)
        if let url = NSURL(string: reviewURLString()) {
            var opened = NSWorkspace.sharedWorkspace().openURL(url)
            if !opened {
                debugLog("Failed to open \(url)")
            }

            }
        }

        let oldKeys: [String] = [AppiraterKey.FirstUseDate,
                                 AppiraterKey.UseCount,
                                 AppiraterKey.SignificantEventCount,
                                 AppiraterKey.CurrentVersion,
