Comparison

Calendar Op.2 vs Tasks+Cal+Sync 4

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Calendar Op.2

Organize your daily schedule with a clean and simple calendar app. It offers a beautiful month and list view with event titles, a mini pop-up for daily events, and seamless scrolling. Easily copy and paste events and search your schedule.

Highlights
  • Works with built-in iOS calendar
  • Month & list view with event title
  • Mini pop-up for daily events
  • Seamless vertical scrolling
  • Copy & Paste for events
  • Incremental search view
Features
Read full description

Calendar Op.2 [opus two] is a very simple and easy-to-use calendar application designed for everyone who loves simple life. With its clean user interface and carefully selected feature set, you can organize your daily schedule smoother than ever. FEATURES: ● Works with built-in iOS calendar. ● Beautiful month & list view with event title. ● Mini pop-up window for daily events. ● Seamless vertical scrolling to the previous and next month. ● Copy & Paste for events. ● Incremental search view. ● Syncing with iCloud, Google Calendar, etc. via built-in iOS calendar.

About

Tasks+Cal+Sync 4

This app synchronizes contacts, tasks, and calendars using the SyncML standard. It's designed for users who need to connect with older systems or specific organizational requirements that rely on this legacy synchronization technology.

Highlights
  • SyncML synchronization for contacts, tasks, and calendars
  • App-internal calendar and task management
  • iOS contact group assignment
  • Acts as a local SyncML server
  • Month, day, week, and list calendar views
Features
Read full description

Please read the following desciption before buying this app! Tasks+Cal+Sync 4 is a niche app, suitable only when you need synchronizing contacts, tasks and calendar with a server or service which uses a standard called SyncML. The app does not support any other synchronisation technology! So please buy this app only if you know for sure that SyncML-based synchronisation is really what you need! This may be the case when the IT people of your organisation say so, and maybe even explicitly recommend using Tasks+Cal+Sync to synchronize calendars, tasks and contacts. In any case, please realize that for using this app, you need to know the URL of your syncml server, the login user to use, and the so called server paths for contacts/tasks/calendar. Only the provider of the SyncML service knows these details and can support you in establishing sync with his SyncML server. We as makers of the SyncML client app cannot! By now, SyncML is a legacy standard. It was invented in 2000, and many of that time's feature phones did support it. Since then, it has been largely superseded by other technologies, most notably CalDAV and CardDAV, which iOS supports out of the box without any extra app. But SyncML still exists, and for some older calendaring systems, it may be the only way to synchronize. For those cases, Tasks+Cal+Sync 4 exists. Tasks+Cal+Sync 4 is a rework of the former Tasks+Cal+Sync app, to allow using SyncML on iOS 10 and later (the original Tasks+Cal+Sync app only works up to iOS 9). But please note that Tasks+Cal+Sync 4 does not provide new features over the original Tasks+Cal+Sync - except for a contact list view with a way to easily assign contacts to groups. Otherwise Tasks+Cal+Sync 4 just carries the original Tasks+Cal+Sync functionality forward to make it usable with iOS10 and later. So now that you are certain SyncML based synchronisation is what you need - here's the summary for Tasks+Cal+Sync 4: • based on a mature and extensively interoperability tested SyncML engine, which powers many SyncML client and server products for different platforms (libsynthesis). • synchronizes app-internal calendar (not the iOS calendar! If you want that, have a look at "SyncML PRO 4"), app-internal tasks (not iOS reminders!) and iOS contacts to a SyncML compliant server or service in the internet or in the local network. • can act as SyncML server in the local WiFi network (e.g. to keep really old mobiles in sync with an iOS device) • has built-in tasks, month, day, week and list views for the iOS calendar (same as in original Tasks+Cal+Sync) • has a contacts list for the iOS contacts, and allows quickly assigning/removing contact group membership (that's a new feature in Tasks+Cal+Sync 4) Please visit the plan44.ch web page (see support link below) for support and FAQ, as well as documentation for download.

Screenshots

Calendar Op.24 screens
Tasks+Cal+Sync 44 screens

Verdict

The call

The clearest difference is price: Calendar Op.2 at Free against Tasks+Cal+Sync 4's $14.99. Calendar Op.2 also leads on rating (4.7 vs 1.0) and update cadence (weekly vs every 20 months). Tasks+Cal+Sync 4's advantage is in-app purchases (none vs 1) and ads (none vs shown). On device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Calendar Op.2 is free to download; Tasks+Cal+Sync 4 costs $14.99 up front. Calendar Op.2 sells 1 one-off in-app purchase. Tasks+Cal+Sync 4 asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Calendar Op.2 holds the better App Store score, 4.7 against 1.0. That said, the two scores are not equally well evidenced: Calendar Op.2 has 13K ratings behind it against 2, so its average is the more settled of the two.

UpkeepUpdate frequency

Calendar Op.2 ships an update weekly, Tasks+Cal+Sync 4 every 20 months. The most recent releases landed on October 28, 2026 and October 16, 2026 respectively.

Scorecard8 real differences · 2 level
Calendar Op.2 versus Tasks+Cal+Sync 4: the parameters behind the verdict, then further details
ParameterCalendar Op.2Tasks+Cal+Sync 4
PriceFree — better$14.99
Rating4.7 (13K ratings) — better1.0 (2 ratings)
Positive reviews68.5% of reviews—
Number of ratings13K — better2
Update frequencyWeekly — betterEvery 20 months
AdsYesNo — better
In-app purchasesYesNo — better
MonetizationFree with in-app purchases — betterPaid
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS26.010.0 — better
Further details — not scored
Size8 MB8 MB
Age rating4+4+
DeveloperYoshihiro SakamotoLukas Zeller

Customer experience

Calendar Op.2

All ratings13,477 ratings
Positive92.1%
Neutral4.5%
Negative3.4%
Written reviews127 reviews
Positive68.5%
Neutral12.6%
Negative18.9%

Tasks+Cal+Sync 4

All ratings2 ratings
Positive0.0%
Neutral0.0%
Negative100.0%

Bugs and requests

Calendar Op.2

Reported bugs

3 issues
  • Events disappearing from past months
  • Time zone issues when traveling
  • Inability to edit event details

Requested features

6 requests
  • Add more color options
  • Implement landscape mode
  • Allow disabling of irrelevant holidays
  • Add support for Apple Watch
  • Improve event editing functionality
Show 1 more
  • Retain past event history

Tasks+Cal+Sync 4

Not enough reviews yet to summarise bugs or requests.

In-app purchases

1 purchases

Calendar Op.2

One-time1
  • Remove Ads$5.99
None

Tasks+Cal+Sync 4

No in-app purchases

Questions

Is Calendar Op.2 free?
Calendar Op.2 is free to download, with in-app purchases available.
Is Tasks+Cal+Sync 4 free?
Tasks+Cal+Sync 4 costs $14.99, with no in-app purchases.
Which has better reviews, Calendar Op.2 or Tasks+Cal+Sync 4?
Calendar Op.2 is rated higher. Calendar Op.2 averages 4.7 out of 5 from 13K ratings, while Tasks+Cal+Sync 4 averages 1.0 from 2 ratings.
Do Calendar Op.2 or Tasks+Cal+Sync 4 have ads?
Calendar Op.2 shows ads; Tasks+Cal+Sync 4 does not.
Which is updated more often, Calendar Op.2 or Tasks+Cal+Sync 4?
Calendar Op.2 ships an update weekly, and Tasks+Cal+Sync 4 every 20 months. Most recently, Calendar Op.2 was updated on October 28, 2026 and Tasks+Cal+Sync 4 on October 16, 2026.

Other comparisons