Thanks for the information. The database version update is a bit odd since my Sage definitely has not updated the database version despite using Kobo Plus since it was available in Canada.
Looking at the .conf file, I do not have the Google Drive bits but the purchase_buy_template, sign_in_page and subs_* match what you showed. This leads me to suspect that they are not related to Kobo's email.
OTOH, according to a usually well informed source, the email was sent to people who have registered ereaders that do not show an update past 4.12.xxxxx. In my case, likely one or more of my older Kobos that I don't use much anymore unless I'm looking at an issue and even then I tend not to update the firmware.
I tested using
howsmyssl.com and the older firmware managed either a TLS 1.0 or TLS 1.1 connection while my Sage managed a TLS 1.2 connection.