Had this light for ages and it was once state of the art. Build quality and operation is superb but it only produced 80 lumens (which was bright once upon a time). I wouldn't have a clue on how to do it but surely there must be someone who can modernize an old light?
https://www.flashlightsunlimited.com/gladius.htm
https://www.flashlightsunlimited.com/gladius.htm