The Wayback Machine - https://web.archive.org/web/20190529205946/https://www.ip-forum.eu/howto-fritz-box-firmware-images-auch-unsignierte-ueber-den-bootloader-installieren-577

For anyone who uses a classic BlackBerry as a secondary device, digital detox tool, or collector's item, having a working copy of this software is essential for ongoing maintenance. You can still manage your device's data, install applications, and ensure everything is backed up, all without needing an internet connection.

Go to Windows Features (turn Windows features on or off) and ensure .NET Framework 3.5 is checked and installed. Conclusion

: Adding, removing, or updating applications through the Application Loader.