No Updater for Linux, you should use wine.
This is a reply from garmin support:
Thank you for contacting Garmin Europe.

I am happy to help with your enquiry.

Unfortunately we do not support Linux operating systems; we only support
Windows and MAC Operating Systems.

I'm afraid we do not have any plans to introduce this.

I'm sorry for any inconvenience.

If there is anything else I can help you with then please let me know.
Alternatively you can search for a solution here:h tt p://www.garmin.co.uk/support

Kind regards,

Garmin Europe