This update is for Skyblock and Islands
Old Level 1 Hopper:
Cost: Free
Sync Range: 10
Items Per Second: 1
Suction Range: 0
Old Level 2 Hopper:
Cost: $100,000 or 60 XP Levels
Sync Range: 20
Items Per Second: 2
Suction Range: 0
Old Level 3 Hopper:
Cost: $200,000 or 80 XP Levels
Sync Range: 30
Items Per Second: 3
Suction Range: 1
Old Level 4 Hopper:
Cost: $400,000 or 120 XP Levels
Sync Range: 40
Items Per Second: 4
Suction Range: 2
Old Level 5 Hopper:
Cost: $700,000 or 160 XP Levels
Sync Range: 50
Items Per Second: 5
Suction Range: 3
How to upgrade a hopper?
If you're not familiar with upgradeable hoppers, simply punch a hopper to open it's GUI. From there you can view current level/info and select an upgrade option.
(To break a hopper, mine it while holding shift.)