M4300 Switch Stack Upgrade Path

Hi,

I have inherited a M4300 stack cluster of 3 24 port switches, which are having issues where one of the stack seems to crash/latchup & is unresponsive

They are running old software 12.9.0.3

Now whilst i would love to upgrade the firmware to latest 12.0.19.21

im finding conflicting information,

if we can go from 12.9.0.3 -> 12.0.19.21

or if we need to stagger with something like this:

[v12.0.9.3] ──> [v12.0.11.16] ──> [v12.0.17.6] ──> [v12.0.19.21 (Latest)]

Reasons i see for stagger is 17.6X breaks admin passwords & possible 15.8+ fixes that

looking for clarification from support or other users, the correct upgrade path.

currently have no access to usb console, & fully remote from these devices..