You remembered correctly. Strollers have actually been in development for quite a while already. Kjun mentioned back in November that they were working on toddler strollers, but stairs/collision/clipping made them technically difficult. They were also included in the 2026 roadmap, and in January Kjun said they were testing babies being seated and moved while remaining interactive.
I couldn’t find anything confirming them specifically for the September 3 update though, so I think they are still planned/in development rather than confirmed for this update.
Here are the Kjun posts if you want to check them. They are included in my quote about different childcare topics:
