This means you have a widget using “logger” instead of “mx.logger”. If you wrote the widget yourself, just change the code to use mx.logger and deploy a new version. However, if this is from a third party widget, you will need to see if there is a new version in the Marketplace to download and update.
Hope this helps.
See the answer from Dawn Dengler in this thread. If you change the log level of the client lognode, the widget will be logged as well