Two versions of stunnel are available - stunnel3 and stunnel4. Normally I would expect the higher numbered version to be the most recent and better supported version. Form some reason I don't know, I'm running stunnel3 and # apt-cache show stunnel reports Version: 2:3.26-dfsg-2 Replaces: stunnel4 Why has stunnel3 replaced stunnel4 on Debian? Which is really the preferred version of stunnel?