It is said that the r4i sdhc dual core,r4i silver rts, r4i gold pro will release the 3DS V6.0.0. upgrade firmware very soon, we just pay more attention their official website to wait for the news:
R4i white dual core 2013 (V6.0.0)------r4isdhc com
R4i silver rts lite 2013(V6.0.0)------r4isdhc com
R4i gold pro 2013(V6.0.0)-------r4i-gold com
Hope the latest updating will come very soon.