The file format for version 1.1.25 and later stores dates in the above-described fashion.
Some internal routines use the time_t type to express seconds. Note that on most OS'es, this is a 32-bit quantity, and is limited to the Unix era (Dec 1901 to Jan 2038).
Backup and log files are time-stamped using the standard Unix ctime() routine, which takes a time_t argument. Thus, the backup and log mechanism may experience trouble in 2038.