OK, since nobody seems to know, I’m going to speculate that this is an (un)planned obsolescence attempt.
It seems to be a way to prevent the continuous expansion of those models beyond the “officially qualified” size: https://myproducts.drobo.com/article/aa-01124
Now, it could be that indeed the 10TB drives are not working in the Pro’s (I honestly don’t see any reason why the 10TB PMR IronWolf shouldn’t, when the 8TB work), or… it could be that DRI is interested in promoting the latest tech, and through the “update” wants to force some of the old clients to upgrade.
I’m not big on conspiracy theories, but I’ve seen worse… so I’ll assume the worst, therefore… unless I see some evidence of serious bugs (and the release notes show that the only bug is the one introduced right now by DRI themselves) it’s my strong suggestion that nobody updates their Drobo Pro past 1.2.2, block off connections to Drobo sites from the Dashboard to kill the prompt, and probably don’t update the Dashboard past the current 2.8.5 (MacOS). We dont’ want things being smuggled into our hardware do we?
Perhaps instead of alienating their clients Drobo should announce what they’re attempting to achieve with this.