MaraDNS has added, in the 1.1 branch, full support for 64-bit timestamps.
On machines with a 32-bit timestamp, MaraDNS is smart enough to convert 
the 32-bit timestamp in to a 64-bit timestamp, which pushes the rollover 
date in to the future.

On 32-bit systems, MaraDNS will work fine until at least 2106 (Mara should 
work fine until 2115.)