If you're using the On Premise Engine on a virtual machine you should deploy the update exactly as follows.
Go to the Task Scheduler, find the task and disable it.
Download the Zip file for the latest version to the virtual machine
Right click on the Zip file and click "Extract to..." and put in the path c:/sigparser
If it asks you if you want to overwrite any files click Yes
Make any configuration changes to appsettings.json and copy it to the c:/sigparser/EmailFetcher folder.
In the Task Scheduler Enable the task again.
Run the task in the Task Manager.
Check the log file at c:/sigparser/EmailFetcher/emailfetcher.log to see if new log entries are being written into it.