For your two open issues:
- Updating an existing extension
- Download the latest version of the extension
- Open your project in App Inventor
- In the designer palette on the left, scroll down to Extensions
- Click on import and select your latest version from your computer
- If all goes well, you should get a notice that your extension has been upgraded
- If it fails, you may need to contact the extension developer about this, or worse case the new extension is not compatible with the previous version. In this latter case, you will have to uninstall the version you have, then install the new version. This will mean a lot of work in the blocks editor! Make a copy of your project and save to your PC before starting this.
- Taifun Screenshot
You have another topic for this here
Taifun Screenshot not working (for me)
Please ask questions about this there