I'm traveling to Kazakhstan this September, and I was wondering what the best way is to refer to the capital city. I know that there were some minor protests over the name change back in March, and I really want to avoid accidentally wading into some kind of unforeseen hot-button political issue. Thank you for your help!
You should probably use the official name Nur-Sultan, but you're not going to offend anyone with Astana. Locals use both names regularly and don't really care that much.
As a Kazakh, I can say that we ourselves are still getting confused with the recent name change. In conversations, people usually go with Astana and then, after a few minutes, someone will remember that it's Nur-Sultan now and everybody will switch (or not, because, again, people don't care). Getting used to changes like this takes a lot of time, some old-timers still occasionally call the city Akmola or Tselinograd (previous names).
There're some political issues around the renaming and people have different opinions about it. But it's not a hot button issue and I'm pretty sure that nobody is going to get triggered by the name itself. Unless you're trying to make some kind of explicit political statement, you won't offend anyone.
P.S. The word "astana" means "capital" in Kazakh. So, technically, the old name can still be applied to the city.