Repository for Cura on Linux is reporting errors

The auto updater on my system is reporting errors when it tries to check if a new version of Cura is available. I get the following errors which started a few weeks ago:

An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://download.alephobjects.com/ao/aodeb wheezy Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 0EB44AD9A71B242AAn error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://download.alephobjects.com/ao/aodeb jessie Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 0EB44AD9A71B242AFailed to fetch http://download.alephobjects.com/ao/aodeb/dists/wheezy/Release.gpg The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 0EB44AD9A71B242AFailed to fetch http://download.alephobjects.com/ao/aodeb/dists/jessie/Release.gpg The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 0EB44AD9A71B242ASome index files failed to download. They have been ignored, or old ones used instead.

Is this a known problem?
Is there a work around?

It occurred to me that I had upgraded my Mint system to 18.1.
I un-installed and re-installed the repository, and it seems to be working now.