I originally followed No-IP’s instructions for installing their DUC on a Raspberry Pi, and thought things were fine until I discovered upon IP change that updates weren’t. Updating, that is. With a little research I came across this extremely helpful site which outlines how to install the No-IP DUC as a service on Raspbian. Be aware, the instructions start from scratch, assuming that you don’t have the DUC installed yet.
For the bit highlighted above, you’re going to instead want to navigate to whatever the directory is that your DUC installation dir is within. In other words, if the NoIP DUC lives in /home/pi/noip/noip/noip-2.1.9-1 you’re going to want to navigate to /home/pi/noip before pulling down and unpacking that .tar as instructed in line 2/3 there. Other than that, this worked like a champ. Thanks site person!