There is a problem when running

[uikmuuyiok]

Environment: windows 10 & TeXLive2023

When running code, the following process occurred

Missing character: There is no + ("2B) in font nullfont!
Missing character: There is no 1 ("31) in font nullfont!
Missing character: There is no p ("70) in font nullfont!
Missing character: There is no t ("74) in font nullfont!
Missing character: There is no + ("2B) in font nullfont!
Missing character: There is no 1 ("31) in font nullfont!
Missing character: There is no p ("70) in font nullfont!
Missing character: There is no t ("74) in font nullfont!
Missing character: There is no + ("2B) in font nullfont!
Missing character: There is no 1 ("31) in font nullfont!
Missing character: There is no p ("70) in font nullfont!
Missing character: There is no t ("74) in font nullfont!

Guess some codes are no longer supported

Add a sentence \def{\nullfont}{a}, found some changes at the top