My first GPS was a Garmin GPS V acquired in 2002 iirc. Then there’s a Geko 301 and a Foretrex 301; Garmin may consider those to be legacy systems, maybe not. I’ll probably fire them all up this weekend and see what happens. The GPS receivers I use as a routine these days should not be effected.

Edit: Just off the phone with Garmin. The only receiver I have that might be effected is the Garmin GPS V which I don’t use. If you have a Garmin receiver go to: https://support.garmin.com/en-US/ and enter your GPS product name. The example used was for the Geko 201. On the line “enter a topic”, type “Date” and hit enter. The article, “Geko 201 Time and Date are Incorrect”, indicates the Geko 201 may have an issue.
I did that for my Geko 301 and the corresponding article does not show, which is Garmin’s way of letting you know they haven’t identified that receiver as having the rollover issue. So it would seem that sometime between the Geko 201 and Geko 301 (~2006), the rollover date issue was fixed — not sure. I thought the only difference was the 301 had sensors, apparently it was more than that.

The only receiver I haven’t been able to check is my GPS V, but it predates the Geko 201 by a few years so it’s probably not going to know the date and time after April 6th. The rest are good to go. That said, I’ll be checking all of them on Sunday just to see.