Addresses are case sensitive, similarly to ethereum, the checksum is calculated according to the address in its case sensitive format and thus it is always recommended to use the address in that way. since everything is hex encoded, the underlying data does not change between the case status, meaning that an all lower-case, all upper-case and case-specific address of same letters, represent the same account, however the checksum can only be calculated correctly if the case sensitivity version of the address is presented