Hi! I understand that your SimpleX Chat app has stopped updating messages, and that can definitely interrupt your conversations. To help me guide you better, could you tell me if this is happening on your Linux device specifically? Also, have you noticed if the app stops receiving any new messages entirely or just stops refreshing the conversation view with new messages?

Meanwhile, here are some initial steps you can try which often fix such issues with SimpleX Chat:

1. Restart the app: On Linux, close the SimpleX Chat app completely and then reopen it. This helps reestablish connections and update messages. Sometimes the app keeps running in the background and doesn't refresh correctly until restarted.

2. Check network connection: Make sure your device is connected to the internet and that there’s no firewall or network setting blocking SimpleX Chat from syncing.

3. Force app restart from settings: If your app has an in-app restart option (sometimes under settings), use that to reboot the app’s internal services.

4. Check notification settings: Sometimes message sync depends on notifications being enabled properly. Confirm that notifications are allowed and set to "Instant" mode if available.

If after these you still don't see new messages updating, let me know. We can then explore more advanced checks like clearing cache, reinstalling the app, or reviewing any recent updates that might have caused this. Also, please confirm your app version if you know it, so I can tailor the advice perfectly.

Are you able to try these steps so far?