I exported the secret part of my master key for security reasons. Now I had to extend the expiration date of my key for six months.
gpg --list-keys in my console, the following appears
pub 4096R/D11FEC22 2015-04-11 [expires: 2016-04-05] uid Prename Lastname <firstname.lastname@example.org> sub 4096R/63FD324E 2015-04-11 [expires: 2016-04-05] sub 4096R/D0A7E7F3 2015-04-11 [expires: 2016-04-05]
Everything seems to be fine.
gpg -K, I get the following:
sec# 4096R/D11FEC22 2015-04-11 [expires: 2015-10-08] uid Prename Lastname <email@example.com> ssb 4096R/63FD324E 2015-04-11 ssb 4096R/D0A7E7F3 2015-04-11
Why is there still the old expiration date? I can sign any messages. Apparently this date has no influence, doesn't it?