While Team Cherry continue working on the Sea of Sorrow expansion for Hollow Knight: Silksong, they've released Patch 5 to keep the game running nicely.

Found this:

Fixed Last Judge’s death explosion doing 3 damage (now 2), and not being reduced by Magma Bell.

Nice.

Magma Bell now protects against all fire-type explosions.

Except Last Judge’s death explosion, I guess xD