And now, after six years of deprecation, the core team has finally announced that SWFUpload will be officially removed from WordPress core. The team first searched the WordPress plugin directory and then compiled a list of plugins that contain references to SWFUpload in their code. According to Western Ruter, the list contains around 128 themes and plugins on WordPress.org.
Among those 128 themes and plugins, below are some of the most popular plugins:
If you use one or more of the plugins mentioned above, then you are highly suggested to get in touch with the author and ask if it would function without SWFUpload in core.
Source: WP Tavern