TimeAdjust is not able to change the file modification timestamps in case that the filesystem uses UTF-8 (or any non-ASCII or non-Latin1 encoding) and there's a file that has a non-ASCII character in its path. Timestamps for ASCII-only files can be successfully processed though. This bug does not affect timestamps in metadata such as EXIF, IPTC or XMP, which can be successfully modified for all files regardless of the characters in their names.

Reproducible: Always

Steps to Reproduce:
1. Create an image with a non-ASCII character in its name or path, e.g. "Besançon.jpg" or "Kraków.jpg"
2. Try to modify its file last modified timestamp via the TimeAdjust plugin
Actual Results:  
Files with non-ASCII characters cannot be processed (Status = "Failed to update file timestamp"), while files with ASCII only characters are updated successfully (Status = "Processed without error")

Expected Results:  
All files are processed successfully

TimeAdjust plugin assumes that all characters in the file path are encoded with Latin1 encoding:
if (utime(m_url.path().toLatin1().constData(), &times) != 0)

Instead of calling m_url.path().toLatin1().constData(), the conversion to const char* should be done by
QFile::encodeName(m_url.toLocalFile()).constData()
which respects the user's locale.