added in config.yml:

experience:
xp-per-level: 500

missions:
kill-mobs:
min-required: 10
max-required: 30
min-xp: 100
max-xp: 200
break-blocks:
min-required: 50
max-required: 200
min-xp: 150
max-xp: 250
kill-players:
min-required: 3
max-required: 10
min-xp: 250
max-xp: 400
mine-diamonds:
min-required: 5
max-required: 15
min-xp: 300
max-xp: 500
kill-endermen:
min-required: 3
max-required: 10
min-xp: 250
max-xp: 400
kill-zombies:
min-required: 20
max-required: 50
min-xp: 150
max-xp: 250
kill-skeletons:
min-required: 15
max-required: 40
min-xp: 150
max-xp: 250
mine-iron:
min-required: 30
max-required: 100
min-xp: 100
max-xp: 200
mine-gold:
min-required: 20
max-required: 50
min-xp: 200
max-xp: 300
kill-creepers:
min-required: 10
max-required: 25
min-xp: 200
max-xp: 300