Lines are quoted from the official notes; buff/nerf tags are auto-classified from the numbers and can be wrong. Covers the 14 most recent Dota 2 patches PatchMeter has fetched.
⇄adjustArmor PowerNow also allows Clockwerk to consume Chainmails to gain +4 armor per Chainmail consumed
▲buffBattery AssaultMana Cost decreased from 90 to 75/80/85/90
⇄adjustPower CogsClockwerk can now move freely through the cogs, sinking them down while walking over them. Other units can also walk over sunken Power Cogs
▲buffPower CogsMana Cost rescaled from 70 to 60/65/70/75
▲buffPower CogsMana Burn increased from 35/70/105/140 to 35/75/115/155
▲buffOverclockingDuration increased from 13s to 18s
▲buffOverclockingNow also increases Battery Assault radius to 330
▲buffOverclockingNow also increases Power Cogs radius to 330 and provides 25% bonus armor to Clockwerk while he is near cogs
✕removedOverclockingNo longer increases Clockwerk's attack speed while inside Power Cogs
▲buffOverclockingNow increases Rocket Flare damage, vision and slow duration by 35%
✕removedOverclockingNo longer decreases Rocket Flare cooldown to 3.5s