It looks like there are just some small resistor changes around the main drive transistor. Makes sense that higher voltages also tally with higher voltage resistors..
PART | 230V | 110V |
R9 | 0.33R | 0.27R |
R2 | 51K | 39K |
R2A | 51K | N/F |
R7 | 33K | 15K |
C5 | 47uF/400V | 47uF/200V |
T1 | 230V / 0.45A | 117v / 0.9A |