Signal is too difficult to be used by my relatives, but do not underestimate the issue. Dad uses the app to work and has not uninstalled, while mom, did the upgrade, came to ask "why the gardener of the nearby sends me pictures while he's kissing his girlfriend?", and then uninstalled the whole, she's now using sms again.
Try getting your Spouse, Accountant, Mom, Uncle etc to make the move.