Disable the security mechanism of a webapplication that was made for me

Project description: A Firm was making a software for our company that is web browser based. The software works great so far. We bought the software from the developers and now they have closed. We need a new license file to use all the functions of that webserver based software. Need somebody who finds out how we can disable the security mechanism of the software to use it without user limit and function limit. The lincense is a text based code that includes all information. We need somebody who finds out how this works and disables this license check. A licence code looks like this: AH1n53kB/jFt/tSEn1LGqTGa2T3q5dHipAMHvcf5+u4971Ktmn/uLCy0IBCK9dPJjfroE7mG+D66azRXId3WSO2u3i9Btxp//Ku8MNMSV9rLfqDZEpjZ2wOb8ONYVAp9rDqBeawVyJbDunGkyPiZ4sh2T+g1t3ccwI67INs5M5MY23yHCIMQhGocSfEK9HSvxM04TLikLp59mhu/TRg3xx8hRw4lo+gfyaV8nBn3Vi+6Fmu9wUkRM6jfej+6J7NxQrVj1heeXDhBE5fIVL9QIkK1Y9YXnlw4QROXyFS/UCLVhR9B/Dv0itwl0MIzinh0 it works together with a serial that looks like this: W043-A100-S66790