applications - Retrieving app messages

Is there a way to (offline) retrieve app messages (messages that appear with on the top right on the home screen with a small icon of the app)

Without opening the app itself? (or when the app doesn't store these messages)

Or is there an app that I can install that can remember these messages?

I am using a Dtek 50 android 6.0

Answer

Notification History records notifications, toasts, Dialog message and many more.

You can configure it store these either for 30 days or 300 Notifications and view off line

From app description:

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