Watched an AOPA webinar on IFlightPlanner updates just last night. You can see it here... https://youtu.be/JPkfwZXmOiY
The sync wtih IFLY is being made available in the free AOPA version until the end of April 2021. After that it will require a Core or Premium account.
What's not obvious to the Free AOPA version users, is that to use it, you need to create an IFlightPlanner username and password to use for the sync. If you have a paid iFlightPlanner account you already have those. If you are using the free AOPA version like I am, you need to go to IFlightPlanner page at AOPA, then click Flight Planner Home > My Account > My Profile > User ID and Password tab....and use the "Change My User ID" and "Change My Password" features to establish your credentials.
Once you do that, go back to IFly and provide those credentials in the iFlightPlanner sync menu. Worked fine for me...no issues.