Since you last played
UntouchedValve’s patch notes record no changes to Quarterstaff since patch 7.06d (mid 2017). It works the way you remember.
What it did before it was removed
- + 10 Attack Speed
- + 10 Damage
Shop item, 875 gold. Removed from the game in 7.35.
Full history
Until you pick a month the page shows every change. Pick the month you last played to keep only what is new to you. The date is shared by every item page.
Valve’s patch notes record no changes to Quarterstaff since patch 7.06d (mid 2017). It works the way you remember.