Hi Annie,
About every 4 to 5 years the i30 gets a fairly big overhall. So it first came out in late 2007, series 2 came out 2012, series 3 came out in 2017, so you would think another major revamp would be in the wings for 2022 at the latest. The updates I have seen for 2021 only look like styling tweaks of the existing PD series 3 model.
I'm guessing the next i30 will probably have a mild hybrid system to improve fuel economy and more autonomy. A fully configureable digital instrument cluster, larger more configurable infotainment screen and additional safety features.