Any changes made before I started drinking it are merely historical baggage, but any changes made after I started drinking it have a fundamental effect on whether I consider it the same product. See also: "New Coke".
(Also, I can taste Aspartame -- so while many people might say that the low sugar variant is sufficiently similar in taste, I really don't enjoy it. Although, as I posted above, this is probably a good thing.)
https://www.verkkokauppa.com/fi/product/327752/Irn-Bru-virvo...
Unfortunately that's the new "not really Irn Bru" recipe :(.
I get what you're saying, and I kinda believe the best Irn-Bru was the stuff in a glass bottle, delivered to the door, when I was a kid.
But the stuff that's out there, to my mind, is still just fine. It cures hangovers. It tastes of sugar and love, whether there's real sugar, real iron, or real love in it is almost immaterial.
Un(?)fortunately I taste Aspartame as being bitter so it's not as sweet for me as it used to be :(. Which is probably a good thing, given how much I used to drink :P.
Although if I'm honest, I drank far too much of the stuff so it's probably a good thing I can't buy it any more.