This is Season 04 with many upgrades.  If you have the avi formats files, just DL the ISOs to get the upgrades.

If you already have all of the standard .avi files, then only select the .ISO files you are missing for download.

Season 04MST3K - 0401 - 20030610 - Space Travelers.avi
Season 04MST3K - 0401 - 20030610 - Space Travelers.iso
Season 04MST3K - 0402 - 20010707 - The Giant Gila Monster.avi
Season 04MST3K - 0402 - 20010707 - The Giant Gila Monster.iso
Season 04MST3K - 0403 - 20011208 - City Limits.avi
Season 04MST3K - 0404 - 20011125 - Teenagers From Outer Space.avi
Season 04MST3K - 0404 - 20011125 - Teenagers From Outer Space.iso
Season 04MST3K - 0405 - 20040330 - Being From Another Planet.avi
Season 04MST3K - 0406 - 20040411 - Attack of the Giant Leeches.avi
Season 04MST3K - 0406 - 20040411 - Attack of the Giant Leeches.iso
Season 04MST3K - 0407 - 20010221 - Attack of the Killer Shrews.avi
Season 04MST3K - 0407 - 20010221 - Attack of the Killer Shrews.iso
Season 04MST3K - 0407 - 20010221 - Attack of the Killer Shrews.mds
Season 04MST3K - 0408 - 20010719 - Hercules Unchained.avi
Season 04MST3K - 0408 - 20040812 - Hercules Unchained.iso
Season 04MST3K - 0409 - 20010716 - The Indestructible Man.avi
Season 04MST3K - 0409 - 20010716 - The Indestructible Man.iso
Season 04MST3K - 0410 - 20020404 - Hercules Against The Moon Men.ISO
Season 04MST3K - 0410 - 20020404 - Hercules Against The Moon Men.avi
Season 04MST3K - 0411 - 20010809 - The Magic Sword.avi
Season 04MST3K - 0412 - 20011024 - Hercules And The Captive Women.avi
Season 04MST3K - 0413 - 20020312 - Manhunt In Space.avi
Season 04MST3K - 0413 - 20020312 - Manhunt In Space.iso
Season 04MST3K - 0414 - 20020321 - Tormented.avi
Season 04MST3K - 0414 - 20020321 - Tormented.iso
Season 04MST3K - 0415 - 20011211 - The Beatniks.avi
Season 04MST3K - 0415 - 20011211 - The Beatniks.iso
Season 04MST3K - 0415 - 20011211 - The Beatniks.mds
Season 04MST3K - 0416 - 20020518 - Fire Maidens Of Outer Space.avi
Season 04MST3K - 0417 - 20010609 - Crash of Moons.avi
Season 04MST3K - 0417 - 20010609 - Crash of Moons.iso
Season 04MST3K - 0418 - 20020206 - Attack of the The Eye Creatures.avi
Season 04MST3K - 0419 - 20010513 - The Rebel Set.avi
Season 04MST3K - 0419 - 20010513 - The Rebel Set.iso
Season 04MST3K - 0420 - 20010504 - The Human Duplicators.avi
Season 04MST3K - 0420 - 20010504 - The Human Duplicators.iso
Season 04MST3K - 0421 - 20010722 - Monster A-Go-Go.avi
Season 04MST3K - 0421 - 20010722 - Monster A-Go-Go.iso
Season 04MST3K - 0422 - 20020910 - The Day The Earth Froze.avi
Season 04MST3K - 0423 - 20010516 - Bride of the Monster.avi
Season 04MST3K - 0424 -  00000000 - Manos the Hands of Fate.avi
Season 04MST3K - 0424 -  00000000 - Manos the Hands of Fate.iso
Season 04MST3K - 0424 -  00000000 - Manos the Hands of Fate.mds