Hi
I have four DrayTek 2820 routers connecting four offices.
But all four router seem to have different firmware. one have eg Firmware Version: 3.3.2.2_232201, 3.4, 3.5
I would like to upgrade firmware on all router, so all router have same firmware.
So can I upgrade to later one, which one is the stable I can go for.

Many thanks

update to 3.3.5.2 first of all, then update to 3.3.7.3, it's a good stable firmware in my experience
Updating to 3.3.5.2 is necessary so that the config file will work with 3.3.7.3 without having to clear and re-do it.