Emoji aren't a fixed set; there are new ones added all the time: 230 this year, 157 last year, …. When I see an emoji, I can't tell whether it's an existing one

Emoji aren't a fixed set; there are new ones added all the time: 230 this year, 157 last year, …. When I see an emoji, I can't tell whether it's an existing one drawn in a different style, or whether it got added since the last time I memorized the code chart.