No this isn’t an April Fool but something to be aware of.
If you have a garmin or similar GPS based unit, especially an older model, there is an outside chance it may not work if it doesn’t have the latest code on the chipset and throws a wobbly.
If you are able to check the firmware and have been keeping It up to date then you’ll likely be ok but sensible precaution is to check it in early April especially if you have a big ride planned where you would rely on it.
If your bit of tech is post-2010 then the manuf should have planned for this.
TheReg has the detail
https://www.theregister.co.uk/2019/02/12/current_gps_epoch_ends/