In addition to my previous post, genuine notifications from Microsoft start with the following:
Also, compare these random sections of the PGP signature.
This is the genuine version. Note how it contains symbols (/ and + in this extract) as well as alphanumeric characters in both upper and lower case.
This is the fake version. Notice how it consists solely of alphanumeric characters (in UPPER case only) - there isn't a symbol in sight.
In addition to that, the length of the signature in the fake email is too short, also the PGP version is not current.