find(1):
-newerXY reference
Compares the timestamp of the current file with reference. The
reference argument is normally the name of a file (and one of
its timestamps is used for the comparison) but it may also be a
string describing an absolute time. X and Y are placeholders
for other letters, and these letters select which time belonging
to how reference is used for the comparison.
a The access time of the file reference
B The birth time of the file reference
c The inode status change time of reference
m The modification time of the file reference
t reference is interpreted directly as a time