While version 6.01 is a specific iterative update, the "Extra" designation usually highlights these features:

Estimated gameplay of depending on reading speed and completionist goals. MILFs of Sunville - Season 1 on Steam

The story follows a young man forced to leave a luxurious city life after his father cuts him off. He moves to the seaside town of Sunville to attend college, where he encounters various romanceable characters, primarily mature women (MILFs). Version 6.01 "Extra" Features