V1.0.0.152:

• Item cost reduced to 2900 from 3105.
• Combine cost reduced to 605 from 700.

V1.0.0.106:

• Slow duration reduced to 1.5 from 2.
• Updated the tooltip to reflect slow information for single target and damage-over-time slows.

V1.0.0.63:

• Slow duration increased to 2 seconds from 1.5 seconds.
• It will now trigger on dealing non-periodic spell damage, instead of spell hit. This means that spells like  Destiny or  Time Warp, which previously triggered the effect, won’t anymore; however,  Rupture will now slow on dealing damage instead of on the initial cast,  Powerball will now trigger the effect when you hit units, etc.

V0.9.25.34:

• Slows from items ( Phage, Frozen Mallet, Rylai's Crystal Scepter) will no longer stack. The largest slow will take effect until duration wears then next largest slow will take effect if it’s still active.

V0.9.25.24:

• Single target slow reduced from 40% to 35%.

V0.9.25.21: Remake.

• Health and ability power.
• Now causes single target spells to slow by 40% for 1.5 seconds (15% for multi target spells).

V0.9.22.15:

• Removed the internal 6 second cooldown.
• Increased proc window from 4 to 6 seconds.

V0.9.22.7: Added

• Rylai's Crystal Scepter:
  • +500 health.
  • +500 mana.
  • +80 ability power.
  • Passive: After a spell cast, your champion's next basic attack reduces your target's movement speed by 35% for 2.5 seconds. This effect can only occur once every 6 seconds.