I would say v1.45 is the latest version as most google searches link to this version,some even say it is a BETA version.
As for the other questions,"unused open with entry"is most probably something you have installed and not used,say like for example winzip/winrar,they are installed and the system knows to open zip/rar files with the app's but hasn't done so yet.
"Extension not used"
is most probably a left over from something you have un-installed,that added file extensions for that particular app.
This is just my way of interpreting them,it may be totally wrong,lol