2.3.3 is the latest "official" version.

2.3.4 has leaked and is floating around on the www but it's not an official release yet.

Hopefully it will be soon.

 

you can obtain the latest official firmwares including 2.3.4 (and some unofficial) online, flash them to your phone using the odin software.

all links/files/instructions etc are here:

[ROM + Guide]Official i9100 Firmwares KF1/2/3/4/, KG1/2/3/5/6/7, KH1/2/3/4 Download - xda-developers

it's a bit mindblowing to begin with but is actually very easy.

 

I flashed mine in Friday - used SAMFIRMWARE.com - bit of a PITA cos of the download limits - one every 30 mins! But downloaded the large file overnight.

Was easy. First time. Also did my misses galaxy mini - had a heart stopping moment there when the first attempt did start lol! Used a later version and it was fine.

Battery life on s2 if around 8 hours better and its slicker and quicker. Only problem is on the lock screen there is an FM radio widget that jams the screen up occassionally - it appears when I get a text message that I haven't read. Just need to hit the power button to unlock it again. Anyone know why it does this?

 

XXKG5, available on the link posted by Sydney99 is official, although still not released via Kies in some regions. and it runs 2.3.4. if u wish to stick to official firmware, flash KG5.. if u dont mind trying out the leaked firmwares available, KH3, which im using, is also a good option

 

If I update to KH3 or KH4 to try them then flash back to KG5 will that wipe my data going backwards?

Also reading instructions to get rid of a yellow triangle after rooting there are steps that I need to take to do so and one of the steps is to download the STOCK KERNEL, just a little confused my phone out of the box was I think KE2 then updated via Kies to KE7 then updated to KG5 via Odin which would be the stock kernel?

 

if you updated to KG5 firmware, and then rooted, the stock file you need to remove yellow triangle is the KG5 stock kernal, found on the same XDA page where you downloaded the KG5 (Poland) package - it's directly below.

and no, going backwards shouldn't wipe data. though if you're rooted and done your titanium backups it wouldnt be an issue anyway.

 

im not sure about flashign back an olded firmware.. generally all the firmwares on that thread are non-wipe unless it says it will wipe ur phone.. but when i initially flashed KG5 over KG6, i had to wipe.. not sure if that was an issue with KG5 or KG6.. anyway, like Sydney said, if ur rooted, use titanium before u flash back, and it wont matter