Consider Maxwell's equation in integral form:
$$\int_{\partial V} \pmb E(\pmb r,t)\cdot \ dS =\int_V\frac{\rho(\pmb r,t)}{\epsilon_0}dV$$
$$\int_\Sigma \pmb B(\pmb r,t)\cdot dS=0$$
$$\oint_{\partial \Sigma} \pmb E(\pmb r,t)\cdot dl=-\frac{\partial}{\partial t}\int_\Sigma \pmb B(\pmb r,t)\cdot dS$$
$$\oint_{\partial \Sigma}\pmb B(\pmb r,t)\cdot dl=\mu_o\int_\Sigma \pmb J(\pmb r,t)\cdot dS+\frac{1}{c^2}\frac{\partial}{\partial t}\int_{\Sigma}\pmb E(\pmb r,t)\cdot dS$$
Where $V$ is a volume, $\partial V$ its surface boundary; $\Sigma$ is a surface and $\partial \Sigma$ its line boundary.
My question is this: for the equation to hold, is it necessary that these volumes/surfaces/lines stay fixed in time, or are they allowed to vary along with the fields and the sources?
For example, if I defined a function $\Sigma(t):[t_1,t_2]\rightarrow S(\mathbb{R^3}) $ , where $S(\mathbb{R^3}) $ is the set of all appropriate surfaces in $\mathbb{R^3}$, would it still be true that $$\oint_{\partial \Sigma(t)}\pmb B(\pmb r,t)\cdot dl=\mu_o\int_{\Sigma(t)} \pmb J(\pmb r,t)\cdot dS+\frac{1}{c^2}\frac{\partial}{\partial t}\int_{\Sigma(t)}\pmb E(\pmb r,t)\cdot dS ?$$
(Notice I've added the time dependency at the bottom of the integral signs)