It's been quite some time since the last update... Ver.4.3c was released in March 2004!
I have sent an email to JARL enquiring if an English version will be produced. Hopefully the entire document will be translated, just scanning through and picking up on English words it seems there is a lot of interesting stuff in there.
I also sent an email to Satoshi, asking him what was new. He replied that there is a new part defining the new data only D-Star mode where the entire 4800 bps D-Star stream is used for data (no interleaved voice/data). This mode will make it's appearance in the soon-to-be-released 50th anniversary edition of the Icom ID-51A/E radio.
Satoshi has also confirmed that existing repeater infrastructure/gateways will be able to deal with this new data only mode.
Seeing as the ID-31A/E, ID-5100 and IC-7100 radios have user upgradable firmware, I hope they will be able to support this new data only mode.