Could be anything. Women can’t really speak for all other women. She could be lonely and looking to flirt, it could be completely platonic and genuine “hey, I miss that person, I should see how they’re doing”, could be that she’s a shitty person who is bored, could be trying to market something... Gender may be relevant here but it may not. I know I’ve gotten in touch with people after a long absence due to depression or whatever. I would hate to think someone read an agenda into it when it was just trying to reconnect.

I recommend going with it if you’re comfortable, see what she says and if you wish to engage, do. But don’t overthink it, you don’t owe her anything.