I totally missed there was a new version out. So I went and downloaded it right now, and ran my usual upgrade steps and v27 is working for me.
Only thing I am doing differently than some could be I have SSL setup with the correct cert/name record.
As a general note having the “Site URL” set is kind of important because it gets sent with the password reset email for users. Having it set to localhost means the reset URL will be wrong and the average user might not be aware of the real URL.