Upgrades for Inspiron 3521

Hello. I currently have an Inspiron 3521 with the usual 4GB RAM . According to the requirements of a software I frequently used, the optimum specs for the laptop should be 16GB RAM with a 4 GB of GPU VRAM, requiring me to call for upgrades. While I can replace the 4GB RAM by two 8GB RAMs, I am unsure about the GPU VRAM. Is there any upgrades/hardware available for this laptop to meet with the requirements/performance of a 4 GB of GPU VRAM? Thank you