The largest and oldest bank here in Brazil migrated all of its ATMs and branch manager desktops from OS/2 to Linux a decade ago; the other large banks I know of in Brazil seem to use Windows for desktops (and probably also their ATMs). I don't know about other countries, but it wouldn't surprise me if their banks have also migrated to something other than OS/2.

I think that was true pretty much everywhere.

I was at the help desk for an large Scandinavian bank doing the late 00ies and they were running virtual OS/2 instances on nearly every windows pc in order to support an custom app, and still had a few front desks(or whatever the window where the bank teller sits is called) with dedicated OS/2 hardware.

The biggest problem here was sourcing dot matrix printers as the software used as the front desk software only worked with a few models of no longer in production printers.

A few years after i left i heard rumors of an transformation project to get rid the legacy interfaces, part of which had been on going for a decade(as an old school java application) by the time i left for greener pasture, but i would not be surprised if that project it is still not complete yet, nor would i be to hear of retail banks that never bothered with any investment to replace OS/2 based apps.