With today's nightly build this occurs

MPY: soft reboot
MicroPython v1.19.1 on 2022-07-08; Arduino Nano RP2040 Connect with RP2040
Type "help()" for more information.
>>> import network
>>> s = network.WLAN(network.STA_IF)
>>> s.active(True)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OSError: Firmware version mismatch. Minimum supported firmware is v1.5.0 found v1.4.8

Previously I was running a build dated 22 April: this error did not occur.

It's also worth noting that the support for MSC mode means that firmware installation by powering up with the button depressed does not work. The docs are therefore misleading to new users: it now seems mandatory to use machine.bootloader().