new battery firmware

Looks like I'm being offered it but I don't know why, what's different from it and 3020? and should I install it asap?

I would recommend no. There is no backup from Givenergy now and the update process isn't entirely stable. There are quite a lot of stories of failures and manual intervention being required. We're on 3020 and whatever the associated inverter firmware is and it's been reasonably good. You may wish to search the forums to find the download link for the various firmware versions and hold them on file. There is also a procedure for manual update should you find this becomes necessary in future.

Marren2016 I would also add, just think of the firmware as software (which it is really) - the upgrade will be there to introduce new features or fix some bugs. If the new features or bugs do not affect you then I can't see any reason to do the upgrade, and that is before you take into consideration that there is no GE support now

I did a search on this forum but it did not reveal and downloads or links to downloads.
I don't know what the changes are in the firmware but I'm buying energy of around 100wh to 300wh each day when it's perfect weather for solar charging.
I've never had an issue with a FW update but if something were to go wrong where could I find help?

It might be worth downloading a copy of newer firmware and putting it somewhere like Dropbox where you can access it in the future for a manual upgrade even if the software division becomes insolvent. That way if there is any bug or fault that requires you to upgrade to resolve it then you have that option.
Otherwise the conservative approach is to leave things be as you only have your installer and this forum for support now.

Does anyone know where I can find the download?

https://givenergy2025.zohodesk.eu/portal/en/kb/documentation/firmware-files

Thanks for that. I cannot see any firmware for the gen1 3.6 hybrid inverter.

You were asking about the battery firmware which is on that page. The Gen 1 inverters have not had new firmware except betas for some time.