Proteus Professional version 8.15 SP1 Build 34318 appears to be a specific release of the software. Here's a breakdown of the version:
Allows for real-time simulation of microcontrollers (including peripherals) alongside mixed-mode SPICE circuit simulation. Proteus Professional 8.15 SP1 Build 34318 -Neverb-
8GB minimum; 16GB or more recommended for large projects. Proteus Professional version 8