How to update to Zephyr 2.6?

I’m running on os x 10.14 with:
PlatformIO 5.2.1 is currently the newest version available.
I’m trying to update nrf52 to zephyr 2.6. When I run:
pio platform update
I get:
Updating platformio/framework-zephyr 2.20600.210721 @ ~2.20600.0 [Up-to-date]

How do I update to framework-zephyr 2.6?

2.20600.210721 is the encoding of Zephyr 2.6.0, datecode 2021-07-21 (YYYY-MM-DD), no need to do anything further.

Is there a version command I should have used? Something that would have returned 2.6 explicitly?

pio platform show <platform> (e.g., nordicnrf52) might show it. It shows it for other packages definitely.

Package framework-arduinoststm32
Type: framework
Requirements: ~4.20000.0
Installed: Yes
Version: 4.20000.210603
Original version: 2.0.0
Description: Arduino Wiring-based Framework for ST STM32 microcontrollers