Missing features
This is a list of features I would like to see implemented in apps that are otherwise useful, or very nearly useful, but where the absence of the features makes it hard for me to adopt.

Can't subscribe to public .isc calendar. How embarrassing for an organization that deals with collaboration.
License model
- Paid • Open Source
Application types
Platforms
- Online
- Software as a Service (SaaS)
- DAVx5
File storage / backup / sync
I highly recommend Tresorit, despite the fact it's proprietary and expensive because of its enormous privacy advantages over things like Dropbox and Google Drive: Tresorit uses a "zero-knowledge" encryption model, stores users data in Switzerland, and great apps for all OSs, including Linux. User data is synced in folders called Tresors but the app is crying out for two additional features:
- Yubikey support
- Set passwords for individual Tresors
License model
- Paid • Proprietary
Application types
Platforms
- Mac
- Windows
- Linux
- Android
- iPhone
- Android Tablet
- iPad
+5Productivity apps
There are many todo.txt-based apps. It's a wonderful idea to keep todos via an open, easy-to-transfer format. But, it's desperately missing a feature for recurring tasks (e.g. complete a task, have it cloned for a week later). That makes setting things like "pay bills" every month a real pain. A script called "Recurrence" has been developed, but implemented by very few todo.txt-based apps, including the absolutely excellent Simpletask Cloudless, although that, in turn, is only available for Android.
License model
- Free • Open Source
Application types
Platforms
- Mac
- Windows
- Linux
- BSD
I feel very reluctant to complain about this app because the developer has done a truly fantastic, fantastic job here. It is easily the best todo.txt-based app I've yet seen. It even supports recurring tasks, which very few todotxt-based apps do. For which reason I can't help but ask: Why, oh why is this little gem available only on Android? Mr, Jensen, please develop a desktop version. Linux would be fantastic.
License model
- Free • Open Source
Application types
Platforms
- Android
- Android Tablet
- F-Droid
+3Fastmail is generally a fantastic Gmail replacement: Firstly, you don't pay with your privacy (it costs a small annual fee), and you get a ton of features. But, it's missing:
Calendar:
- Search function
- Repeat events only on weekdays
License model
- Paid • Proprietary
Application types
Platforms
- Online
- Android
- iPhone
- Android Tablet
- iPad
+6