When you click on delete attachment from messages you get a 404 error page

@oscman
Nice catch, there is problem with definition of route in plugin.
Go to index.php of messenger plugin and find:
osc_add_route('im-delete-attachment', 'im-delete-attachment/([0-9]+)/([0-9]+)/([0-9]+)/(.+)', 'im-delete-attachment/{thread-id}/{del-att-message-id}/{del-file-name}/{secret}', osc_plugin_folder(__FILE__).'user/messages.php', true);

Replace with:
osc_add_route('im-delete-attachment', 'im-delete-attachment/([0-9]+)/([0-9]+)/(.+)/(.+)', 'im-delete-attachment/{thread-id}/{del-att-message-id}/{del-file-name}/{secret}', osc_plugin_folder(__FILE__).'user/messages.php', true);


(third parameter allowed only numeric values, however name of file is string)

Thanks