In V11 and later, '1234' is interpreted as a character string. In V10, this value was treated as a hexadecimal string (arbitrary character strings were not supported in V10).
Example:
INSERT INTO mybinary values('1234');
INSERT INTO mybinary values(x'31323334')
In V11 and later, both the above inserts insert the same value. In V10 they would both be treated as hex strings.