Hi, I've hit a hurdle. I'm trying to upgrade from 3.0.24, but have stunbled at the apt-get update stage with this error. Any ideas?
W: GPG error: http://apt.puppetlabs.com trusty InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 7F438280EF8D349F
W: GPG error: http://apt.puppetlabs.com trusty InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 7F438280EF8D349F