I am having a problem with one of your extensions that is causing an error "0 Call to undefined method... File::read()" after an upgrade from Joomla 3.9 to 4.2. You can see the full effect that it has on one of my site pages at: www.cftech.com/en/information-resources and I believe a couple of other pages it may have affected as well. It is likely due to depreciated code in the file. Do you have a fix for this? Looking forward to your response.

File::Read() is depreciated in Joomla 4 just change that method to file_get_contents()

api.joomla.org/cms-3/deprecated.html#src/Filesystem/File.php