eZ Publish is currently using 32 bits dates, this causes problem for dates > 2038-01-19 or dates < 13-12-1901 20:45:52.
The year 2038 problem may cause some computer software to fail at some point near the year 2038. The problem affects all software and systems that both store system time as a signed 32-bit integer, and interpret this number as the number of seconds since 00:00:00 UTC on Thursday, 1 January 1970. The furthest time that can be represented this way is 03:14:07 UTC on Tuesday, 19 January 2038 (2147483647 seconds after January 1st, 1970).
Times beyond this moment will "wrap around" and be stored internally as a negative number, which these systems will interpret as a date in December 13, 1901 rather than January 19, 2038. This is caused by integer overflow. The counter "runs out" of usable bits, "increments" the sign bit instead, and reports a maximally negative number (continuing to count up, toward zero). This is likely to cause problems for users of these systems due to erroneous calculations.
Further, while most programs will only be affected in or very close to 2038, programs that work with future dates will begin to run into problems much sooner. For example, a program that works with dates 23 years in the future will have to be fixed no later than 2015.
Because most 32-bit Unix-like systems store and manipulate time in this format, it is usually called Unix time, and so the year 2038 problem is often referred to as the Unix Millennium Bug.