I need a proof or source for this identity:
$ \zeta '\left(z,\frac{q}{2}\right)-2^z \zeta '(z,q)+\zeta '\left(z,\frac{q+1}{2}\right)=\zeta(z,q)2^{z}\ln 2$
Here the derivative means the derivative by the first variable.
Any similar identities, particular cases and generalizations are very much appreciated.
This identity follows from the following distribution relation on the Wikipedia page: $$\displaystyle\sum_{m=0}^{n-1}\zeta\left(z,a+\frac{m}{n}\right)=n^z\zeta\left(z,na\right).\tag{1}$$ It suffices to set therein $a=\frac{q}{2}$, $n=2$ and differentiate once with respect to $z$.