@toggerybob, the error you're seeing from Wordfence (which I use myself) is unrelated to the topic in this thread. Also, this plugin does already use the standard WP update process for updating itself via the WordPress repository.
The error you've received is caused by Wordfence's settings. You have enabled the Wordfence option "Scan plugin files against repository versions for changes" which causes Wordfence to trigger an alert even when the readme.txt file in the plugin repository is changed by a single character. This is overzealousness on the part of Wordfence, and it's not an indication of the DBManager plugin developer doing anything wrong.
In short: plugin developers like Lester often need to update their readme.txt file to make a small and insignificant change to it - eg. to correct a typo, or to add support for the latest version of WordPress - but where the plugin code itself has not been modified at all - for that reason, it doesn't warrent releasing a new version of the plugin. Only the readme.txt file has changed. However, Wordfence detects this change and issues an "alert" for it, which makes it sound like something bad.
You can either ignore the alert from Wordfence, or you could perhaps add "readme.txt" to the Wordfence option called "Exclude files from scan that match these wildcard patterns".