 Variable-width encodings in the Unicode standard, in particular UTF-8, may cause an additional need for canonicalization in some situations.Namely, by the standard, in UTF-8 there is only one valid byte sequence for any Unicode character, but some byte sequences are invalid, i. e. cannot be obtained by encoding any string of Unicode characters into UTF-8.Some sloppy decoder implementations may accept invalid byte sequences as input and produce a valid Unicode character as output for such a sequence.