Hello Sally,
I’d be happy to help with this issue!
So from what we know of the macOS update to 10.15 Catalina, the 4K port on the dock should not be affected as this port is driver independent. The 2K HDMI and DVI ports, Ethernet, and audio in/out are all built into the DispayLink chipset in the dock and will be affected by the upgrade, requiring a driver update.
Here’s a snippet from our website from our most recent blog post about these issues:
"With the recent release of macOS Catalina 10.15, Apple has made changes to the operating system that require an updated beta DisplayLink driver and a few special steps during the installation process in order for any DisplayLink-based device (Plugable brand or otherwise) to work properly.
As a courtesy we have provided detailed installation instructions (and a video walkthrough) for removing any existing DisplayLink drivers and installing an updated DisplayLink driver on a macOS Catalina 10.15 system here –> https://plugable.com/drivers/displaylink/mac/#install_catalina
***** Please pay particular attention to the security processes shown in steps #11, #12 and #13 of the install guide. These need to be completed in order for the process to work.
****** We have had reports that even after following the installation instructions the DisplayLink device is still not working. Should that prove to be the case, first ensure you have a full system backup using Time Machine as a precaution. Once the backup is verified, please follow the instructions provided by DisplayLink here –> https://support.displaylink.com/knowledgebase/articles/1925041-macos-catalina-10-15-black-screen-or-only-one-mon"
Full blog post here: https://plugable.com/2019/10/10/plugable-displaylink-products-and-macos-catalina-10-15/
Please don’t hesitate to let us know of other questions.
Thanks again for contacting Plugable support and best wishes!
Joshua Henry
Senior Engineer
Plugable Technologies

http://plugable.com | http://performance.plugable.com/