There is no proper fix for v1.23...
I first installed the 1.19-1.21 fix.
Then I extracted the 2 official patches & copied 1.23 over 1.22.
Then I copied all that over to dev_hdd0/game/BLxxxxxx
I get the 1.22 fix: I modified the 1.22fix-eboot from blus to bles & from 1.22 to 1.23
then I changed the param.sfo to 1.23
After all I copied the 4 files to ps3:
EBOOT.BIN (modified to 1.23)
PARAM.SFO (modified to 1.23)
default.self (from the 1.22fix) [Cannot modify it
default_mp.self (from the 1.22fix) [Cannot modify it
But it is playable online...