A new firmware update is now available for PS3 - but you only need to bother downloading it if you live in Japan.
As reported on the US PlayStation blog, PS3 owners in other regions won't be prompted to download update 2.43. If you're that bothered, however, you can select the 'System Update' setting in the XMB and get it anyway.
"If you do perform the update, it will not cause any issues with your system or add any new functionality," says Sony. So it's not worth it, in other words, unless you're a mad completist. Oh well.