Does the almsgiver pay the zakat on his salary for all that he has accumulated at the time of paying the delayed zakat, or should he consider what he had at the completion of the hawl (one lunar year)? And is the date of paying the delayed zakat considered the beginning of a new hawl, or does the hawl remain linked to its original date?

The Zakat (definition) payer is not obligated to combine the Zakat of money that has not completed its (lunar) year with money on which Zakat has become due, as long as it is not profit generated from the money on which Zakat became due. And whoever delays paying Zakat without a valid excuse is feared to be sinful, because it is obligatory to pay it immediately according to the majority of scholars, and the (lunar) year for the money remains at its original due date.