It was updated in Sep 2021 from version 1.7a (2013) to the latest at that time version of 1.22c
It looks like since Sep2021 you are the first person to be trying to use sslh as it looks like the configuration process for sslh was changed significantly between 1.7a and 1.22c and the old configuration process no longer works as the options that are used in the init script (-s & -l) are no longer recognised.
To get sslh working, either with the current version or the latest version will require someone to create an update patch that uses and knows the package and how to get it working for the situation of a firewall.