Hello everyone!
Here at shopfiles.com we tested and make sure that our software is up to date and you should not have any troubles with the latest changes PayPal just announced. Long story short the update is mostly server related and ensures that the encrypted communication between you and PayPal is secure. The old encryption was via 22 year old protocol which with today's computing power is considered insecure by PayPal.
So regarding the latest QuickSell update, there's nothing to worry about. It will work as it should. The changes are mostly server related, so your hosting provider must make sure their software is up to date and that the VeriSign root certificate is installed/updated on their machine(s).
Thank you and let me know if you have any questions!
Please make sure you are updated to the latest version of QuickSell File Seller Plugin for Joomla!
Cheers!