Multiple realities(covers information from several alternate timelines)
Mark Stimson was a Starfleet officer in the 24th century.
In 2374, he was listed as a Research and Development officer on a dedication plaque for the USS Prometheus. (VOY: "Message in a Bottle", dedication plaque)
In an unknown, alternate future timeframe, he was listed as an Advanced Technologies officer on the dedication plaque of the USS Pasteur. (TNG: "All Good Things..." dedication plaque)
This character was only mentioned in writing.