Maximum principles (weak, strong) for semi-linear parabolic equations?

The scalar reaction-diffusion equation $$u_t=u_{xx}+f(u)~~(*)$$ with some non-linearity $$f(u)$$ is a semi-linear parabolic pde.

I know that for linear parabolic pde there are the weak maximum principle and the strong maximum principle, see here https://en.wikipedia.org/wiki/Maximum_principle.

I guess these does, in general, not hold semi-linear parabolic pde as $$(*)$$?

Are there similar statements?