Block Set Upgrade is a persistent reel modifier where, after all block symbols are cleared from the grid in a single cascading sequence, the available symbol pool for future block drops is permanently enhanced.
This powerful feature ensures that for the remainder of the current game round (typically a bonus round like free spins or super free spins), only high-value Multiplier, Bonus, and Gem blocks will appear in the designated blocks area.
It significantly shifts the game's volatility and payout potential by removing lower-value or generic block types.