If you want to get the latest update, you could download firmware from hereviewtopic.php?f=192&t=213272
Download SP Flashtool from hereviewtopic.php?f=192&t=319505
Follow instructions from link above.
On the other hand, if you're not experiencing any problems, I would suggest you don't upgrade and wait for the next (local) upgrade. Flashing rom could risk turning your phone into a brick if you don't follow the instructions exactly.
In any case, good luck!