Fix upgrade Jenkins on Ubuntu

While I am updating Jenkins server - see:

W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://pkg.jenkins.io/debian-stable binary/ Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY FCEF32E745F2C3D5
W: Failed to fetch http://pkg.jenkins.io/debian-stable/binary/Release.gpg  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY FCEF32E745F2C3D5
W: Some index files failed to download. They have been ignored, or old ones used instead.

How to fix:

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys FCEF32E745F2C3D5

Output:

Executing: /tmp/tmp.ABvN67J5Hp/gpg.1.sh --keyserver
keyserver.ubuntu.com
--recv-keys
FCEF32E745F2C3D5
gpg: requesting key 45F2C3D5 from hkp server keyserver.ubuntu.com
gpg: key 45F2C3D5: public key "Jenkins Project <jenkinsci-board@googlegroups.com>" imported
gpg: Total number processed: 1
gpg:               imported: 1  (RSA: 1)

Try to upgrade:

$sudo apt upgrade
Reading package lists... Done
Building dependency tree        
Reading state information... Done
Calculating upgrade... Done
The following packages were automatically installed and are no longer required:
 linux-aws-headers-4.4.0-1110 linux-aws-headers-4.4.0-1111 linux-aws-headers-4.4.0-1112
 linux-aws-headers-4.4.0-1113 linux-aws-headers-4.4.0-1114
Use 'sudo apt autoremove' to remove them.
The following packages will be upgraded:
 jenkins
1 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 66.9 MB of archives.
After this operation, 825 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:1 https://pkg.jenkins.io/debian-stable binary/ jenkins 2.263.2 [66.9 MB]
Fetched 66.9 MB in 12s (5,188 kB/s)                                                                               
(Reading database ... 222449 files and directories currently installed.)
Preparing to unpack .../jenkins_2.263.2_all.deb ...
Unpacking jenkins (2.263.2) over (2.235.2) ...
Processing triggers for systemd (229-4ubuntu21.29) ...
Processing triggers for ureadahead (0.100.0-19.1) ...
Setting up jenkins (2.263.2) ...
Installing new version of config file /etc/init.d/jenkins ...
Processing triggers for systemd (229-4ubuntu21.29) ...
Processing triggers for ureadahead (0.100.0-19.1) ...

Done.