Amazon have been sending regular emails to announce that they are upgrading the Product Advertising API (i.e. PAAPI) to version 5 from version 4.
This will happen on the 9th March 2020. After this date, version 4 of the PA API will no longer be available. That means any plugins, apps or services that are not upgrading will stop working.
The good news is, Fresh Store and OneAzon have already been updated to use this version and there is nothing you need to do (except make sure you are upgraded!).
Here are some upgrade guides to help you if you are not sure:
If you have any questions, just drop a message to support and we will be happy to help you.