Oops, I have forgotten to check in firmware 2.0.3 source code. Just did it a minute ago. The twi issue was because some old Wire.cpp / Wire.h files were left in the folder. They are now removed. Check to see if the newly checked in files work. Also if you have hardware 2.1 make sure you also update your Arduino/hardware/aopensprinkler/boards.txt file as it contains the board profile for 2.1 (runs at 12MHz with USbasp bootloader, vs. 2.0 running at 8MHz with USBintyISP programmer).