Win 10 definitions last update – 1.235.3184.0 – 19/02/2017 created at 06:14.
Not listed under Windows Update history. Win 10 defender I thought updated automatically independently. In fact there’s an update button in Windows Defender to check for definition updates whenever you want.
Oh and firewall – these days most home users are behind a NAT router, which acts as a pretty effective firewall against inbound connections as you have to deliberately open inbound ports (yeah yeah, okay, UPnP… just turn that off if you’re worried). Outbound is less of a concern than security vendors make out. If you’re infected by a virus or malware then yes it can block unwanted outbound connections, but if you don’t get the stuff in the first place it’s less of an issue. Plus many ISPs build a decent enough firewall into the routers for both inbound and outbound.
Exception however is a portable device on a public network. But then you’re being very (alarmingly perhaps) trusting with an open public wifi 😉 . Besides though, Windows itself also has a decent enough built in firewall too, and doesn’t get in the way.