The problems are not just software. They have some actual hardware problems as well with reports of screens randomly dying and needing to be replaced.
OK, that explains it a bit more because I know it's easier/cheaper to make a single platform than make two. However, the summary makes it seem like this is a total redesign (with a new software stack) rather than merely fixing what was broken. New hardware is good, entirely new bugs is less good.
What behaviour? At no point are they dropping support. In fact this is the opposite, they are upgrading hardware and continuing to support and making support easier for them without expense to you.
This is my fault, I misread "replace the central computer of every 2025 EX90 with the new one from the 2026 EX90" as "replace the central computer of every 2025 EX90 with the new one in the 2026 EX90" which implies they simply moved on.
I've grown far too accustomed to seeing hardware manufacturers abandoning products the moment they've sold them and it's good to see Volvo actually making it right. However, I hope Volvo provided the option to disable anything that wasn't part of the original purchase as it may be undesirable/buggy.