Is there a Calendar Op.1? What does "Op.2" mean?

There’s only one version: Calendar Op.2. There’s no “Op.1” or “Calendar 1” — Op.2 is the first and only release.

“Op.” stands for Opus (as in a musical work), so the name is read “Calendar Opus Two.”

But the “2” carries a quiet meaning of its own. The App Store is full of calendar apps packed with menus, options, and features most people never use — impressive on paper, yet cluttered and tiring to live with every day. Calendar Op.2 was made as a second choice for anyone who’s had enough of that: a calm, simple, beautifully focused calendar that stays out of your way and simply helps you see your day.

So if you’ve come across a mention of “Op.1,” it’s just a misunderstanding — the app you’re looking for is Calendar Op.2.