The "21" designation specifically aligns with Ericsson's 2021 release cycle , which introduced:
And I was. Because some friendships don’t need eyes to see each other. Just a little link. mini link craft 21
While it shares part of its name with hobbyist products, it is professional telecommunications equipment. Below are the two most relevant interpretations: mini link craft 21
Technicians use Craft 21 to perform software upgrades on the node hardware, manage licenses, and extract inventory data for network auditing. 4. Evolution in the 21-Series Release mini link craft 21