I have always used mature_male/female for posts with age difference, but recently I stumbled upon the older male/female tags, which have a significantly lower post count.

The wiki page for older_male suggests that it could be aliased to mature_male:

A tag used to refer to any 'mature' males in anthro art. Not necessarily old, but older than the average male in art

Or should they be implicated instead (e.g. older_male/female -> mature_male/female)?

I'm pretty sure Older is used to denote age difference between two or mroe characters, while any older than normal character would get Mature.

From what I understand, older_* is more of an age difference tag than anything. It was also created long before mature_* was, so it's meaning has likely been blunted over the years.

Either way I see no reason why they couldn't be disassembled and/or aliased to mature_*.

parasprite said:
Either way I see no reason why they couldn't be disassembled and/or aliased to mature_*.

-1 on aliasing them. I has one reason wai:

post #785777: Both look young but the one above is certainly older

I'm pretty sure there are way more, but can't find them since it's a thing I don't actively look for.

Random said:
I'm pretty sure Older is used to denote age difference between two or mroe characters, while any older than normal character would get Mature.

You have a point. Maybe it's a better idea to implicate younger_male/female/intersex and older_male/female/intersex -> age_difference instead.

Edit: Appearently the older/younger_intersex tags didn't have any posts, which I took for granted since mature_intersex exists alongside mature_male and mature_female. Could they still be implicated so we can use them in the future?