In Conformal Field Theory Philippe by Di Francesco, Pierre Mathieu David Sénéchal
Sec 10.l. Conformal Field Theory on the Torus
eq.10.9 says the modular transformation $\mathcal{T}$ and $\mathcal{S}$ satisfies
1. $$ (\mathcal{S}\mathcal{T})^3=\mathcal{S}^2=+1 $$
But I also heard that given chiral central charge $c$ $$ (\mathcal{S}\mathcal{T})^3=e^{2 \pi i c/8}\mathcal{S}^2 $$
I also heard that $$ (\mathcal{S}\mathcal{T})^6 =\mathcal{S}^4=+1 $$
How can these three statements all be true? Please kindly correct any mistake any of us made above and provide an explanation?