UTF8 Encoding is a type of unicode encoding,  UTF-16 encoding is the encoding for some programming language strings.

utf8 uses at most 4 bytes. 

0{7}

110{5} {10{6}}*1

1110{4} {10{6}}*2

11110{3} {10{6}}*3

The boundary bits are 10{6}, plus the 3 leading series.

https://baike.baidu.com/item/UTF-8/481798?fr=ge_ala