The announcement was coordinated with Apple, Facebook, Google, Microsoft, and Mozilla will prevent all operation of Flash software on all devices in 2020. In September 2019, Microsoft announced that on December 31, 2020, Flash will be entirely removed from all browsers via Windows Update. All .swf and stand alone flash projectors will no longer work on any apple or microsoft product when the roll out is complete. A few google searches will better explain it in more detail as to why.
Edit: This was announced in 2017 but Fen and several other Flash developers are only just now migrating their development platform to something newer.