Welcome to the forums, waleedqk

If you mean system updates (rather than app updates), you'll usually see news of an update here in the forums. You can also go into your eDGe settings and set it for automatic update notifications ("Menu" - Settings - eDGe Settings - Default Device Preferences - Automatically Check for Updates).

To date, updates haven't affected data (journals, PDFs, ebooks). Apps usually aren't affected, although in some cases you may discover that you need to uninstall/reinstall an app you installed, but this isn't common.

Feel free to ask questions!