That's the same version as on Nuuksio

What patch?

Is this analogous to Firefox versions?
Firefox 45.9.0 ESR was the last version of that cycle, some time in 2017.
So what's 45.9.1 then?
What is the Security status of that version?
And - I don't know how you call this - compatibility with modern website features?
Please help me understand this - opinion, technical data, experience, all welcome. Thanks.