Recently Idera has updated their GPG key which they utilise for their APT repositories, and it has been causing a few issues with Ubuntu Systems.
When running an apt-get update, you will find the below error occurring
W: GPG error: http://repo.r1soft.com stable Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 1BF3530AA40384ED
In order to get this repository working again, you must update to use the new key. Use the following commands to import the new key:
apt-key add r1soft.asc