It runs with 5.5.3–pt_BR !
(1) I tried 25MB in the plugin config, to begin with...
But I got:
"Unexpected response from the server. The file may have been successfully uploaded. Check the media library or reload the page."
Working on that...
(2) Uninstalling the plugin changes the maximum size from 2 to 8MB.
(3) There's no use changing php.ini -> upload_max_filesize = 25M in [$HOME] or [ $HOME/php ] directory (I´m hosted).