In reply to a post by MHC:

My S450A-GO which is the same as an N300A-IP is currently at: 42.263

I've always used the UI firmware update button and I've just checked and I'm on 42.263, people can I believe update by downloading the bin file which can be searched for on the internet. I'm reluctant to post a link here as I have never done it that way myself and can't say if it works or not.

Mine is set to Auto Update - it happens very rarely maybe every 6 months or more.

Mine is now, I do tend to auto update most things these days