What does everyone really mean by "I hope you're doing well"?

People who I've been close to in my life who I've separated myself from (for good reasons) are coming out of the blue and saying "hope you're doing well". I know that sounds weird for me to be confused by, but what do they really mean? I wouldn't necessarily say that to them. It may just be a formality, or them being polite, but do you think there's a hidden meaning? Like, "I don't really care but I have to say this to look like I do" or "Have a nice life *******". Wow I look paranoid, but this is how I see it.