The command is
wmic bios get serialnumber
http://www.dell.com/support/article/uk/en/ukbsdt1/sln268357/how-to-locate-system-service-tag-using-command-prompt?lang=en
I have tried it on other brands too. As it seems, it works for Acer machines too.
wmic bios get serialnumber
client max protocol = SMB3This line should be put right after the line
Now I can browse and open share folders on my Windows machines in the network as it used to be.
workgroup = WORKGROUP