when i logged in to my customer portal account, i found the serial number in the cad admin dashboard showed with 16 digits not 24

when i logged in to my customer portal account, i found the serial number in the cad admin dashboard showed with 16 digits not 24.

so,

why and when it is used 16 digits instead of 24 ?

what is the difference between 24 digit and 16 ?

is there any option to preview the full 24 digits ?

anybody knows ?

SolidworksAdministration