And it's more than that. Right now, there's a lull in new firmware releases. I don't think I've ever seen it go so long in the 5+ years I've been watching.
I don't believe new cars will be updated until there's a new release past 2020.4.10. If you want to see that happen in (more or less) real time, then watch TeslaFi (
TeslaFi.com Firmware Tracker). If you want to be informed the moment TeslaFi sees a new release, then follow them on Twitter. And even then, it will be a while after a new version appears (at least a week) before it gets pushed to new cars.