Hi! I use both Book Collector on my Mac and CLZ Books on the iPhone.
When I fill the Box Set field of a particular book on my iPhone CLZ Books it is not reflected on Book Collector on the Mac.
And the same happens the other way around: if I change the Box Set on Book Collector it is not reflected on the CLZ Books.
Box Set was added to the mobile apps and sync code for Windows around January of 2023.
However: All development on the macOS editions of our software have already been stopped since Feb 1, 2021, meaning that the box set field (and a couple more fields actually) never made it to the sync for the macOS version.
I strongly recommend to switch to our Book Connect web-based software ASAP, using our generous Trade-In Offer.
Book Connect is easier to use and easier to manage, while still giving you all features and customization options. And it is has our full development focus, giving your regular updates with improvements and new features.
If you switch to Book Connect with our Trade-In offer, we will trade-in your remaining Book Collector subscription days and will transfer them to the Connect edition, plus we will add 4 extra months for free.
Full details about the advantages of Book Connect, and our Trade-In Offer can be found here:
Let me know if you are interested or have any questions about switching to Connect.