Source file: modules/widgets/gallery.phpView in GitHub
(bool) false Whether to force-enable the gallery widget
Since: Jetpack 5.5.0
You can use this filter to always use the old Jetpack Gallery Widget instead of the new Gallery Widget added to WordPress in version 4.9.
add_filter( 'jetpack_force_enable_gallery_widget', '__return_true' );
Could you include ‘detailed’ instructions on how and where to implement the code for the widgets. Photo widgets seem fine but videos on the home page of the 2014 theme are all lost.
To use this filter you just need to copy and paste the code in the Notes section somewhere in your WordPress site code. But I’m afraid this won’t change anything about the way Jetpack handles videos. If you have a problem with sidebar widgets, can you please create a new support ticket? Our Happiness Engineers will be glad to help you.