They said it was so-dimm. He also said they listened to users and heard them and made the memory upgradable. It is on the Mac mini page, scroll down. It’s where they talk about opening it up and upgrading it yourself.
Read the text, it says nothing about end-user upgradability...
It clearly says 'configure', meaning to configure the SG mini with the amount of RAM you want when you order it...
As others have stated, we will need to wait until iFixit does a teardown for more info on actual -end-user RAM swapping, and if the T2 security chip requires use of the Apple Diagnostic Tool to 'reset' the system after the upgrade for proper functionality...
I would be comfortable tearing down a mini for upgrades, it is the possible requirement to use the Apple Diagnostic Tool afterwards that would worry me, as I do not have that bit of software on hand...