The Old Persian block spans U+103A0–U+103DF, 64 codepoints in Plane 1 (Supplementary Multilingual Plane). 50 are assigned in Unicode 16.0; the other 14 are reserved for future characters.
All of its characters belong to the Old Persian script.
By general category: 44 other letters (Lo), 5 letter numbers (Nl), 1 other punctuation (Po).
The first 50 arrived in Unicode 4.1 (2005).
Because it lies outside the BMP, every character here takes four bytes in UTF-8 and a surrogate pair in UTF-16.