I tried to retitle the bug report 1152141 yesterday but got an error: Therefore, I closed 1152141 and opened 1152194 instead with the title I wanted and a few minor corrections. Still, the issue remains for future bug reports. First, though the degree symbol ° (U+00B0 Degree Sign) is not part of ASCII, it's printable, so the error message was confusing. Second, is anything so bad or so wrong about ° in the second argument of retitle? IMHO, this symbol should be allowed for.