Hi there! I understand your Filtrete Smart app isn't updating after you installed a new filter on your iPhone running iOS 18.6. Let’s work through this together.

First, just to clarify: When you say the app is "not updating," do you mean it doesn’t recognize the new filter installation, or is it not refreshing the filter status or notifications? Any extra details will help me guide you better.

Meanwhile, here are some straightforward steps we can try:

1. Keep the app open: Sometimes, it may take a few hours for the new filter data to fully upload to the app and cloud. Make sure your Filtrete Smart app stays open in the background and your phone remains nearby for Bluetooth connection.

2. Check Bluetooth: Ensure Bluetooth is turned on your iPhone. Filtrete Smart relies on Bluetooth to communicate with your filter. You can toggle Bluetooth off and back on again via Settings.

3. Restart the Filtrete Smart app: Fully close the app (swipe up from the bottom and swipe the app off) and reopen it.

4. Check app version: Go to the App Store and confirm your Filtrete Smart app is updated to the latest version.

5. Re-pair the filter: If none of the above helps, remove the filter from the app (if the option exists), then add it again by tapping the "+" button in the app and following the pairing instructions.

If you've tried any of these already, let me know which ones so we can dig a bit deeper or explore more advanced steps.

Does this sound like a good start?