It is a common misconception that Mormons are not allowed to consume caffeine, the limitation is actually on "hot drinks," which is interpreted as having meant tea and coffee specifically in the time it was written down. They still drink soda and other heated drinks such as wassel, hot chocolate, and postum (a morning coffee substitute most folks find absolutely disgusting).
(we live near a de facto Mormon college and pester our neighbors, who are largely Mormon professors, about such things)
My understanding is that it changed in 2012 - the church released a statement then saying that the prohibition only applied to coffee and tea. Before that, it was ambiguous but customarily interpreted to apply to all caffeinated drinks.
As a (anec?)data point, I had a Mormon friend growing up and they drank caffeine-free Coke for this reason.
It seems many things have officially changed-but-always-been-that-way :P Everyone's got old-timey atlas prints of central America instead of upstate NY now.
Seems to be, at least with some of the families around here! A bunch of them also get together and do caroling around the holidays, so maybe it's related to that?
Most of them seem to drink soda here; in fact, we have a Mormon-owned soda shop in town that a lot of the school-age Mormon kids seem to hang out at! I've been told it's often a regional thing, that they're less "Mormon-y" (their term, not mine) if there's a community of them in the area. I suppose it's probably like any other group, and they feel less like outsiders.
Kinda interesting being somewhat immersed in what's effectively a conservative subculture that's supposed to not shun folks who aren't part of it. We have some weird conversations.
(we live near a de facto Mormon college and pester our neighbors, who are largely Mormon professors, about such things)