Simple-Calendar: offline is the headline, syncing anyway is the feature list

The app names a year that has already passed

The readme calls the product Simple Calendar 2023, repeatedly, in headings and in the download line, and the tagline describes it as a planner designed to do what such a planner should do in 2023. That is a marketing decision with an expiry date, and it has expired: the most recent tagged release is from October 2023 and the most recent commit to the branch is from June 2024. Nothing in the file suggests the app is abandoned, since the repository is not archived, and there is a changelog at the root rather than a farewell notice, but anyone arriving from a search today is reading a page that describes a release two years back. One small detail in the same area is worth knowing before you install: the package listed on the third-party app store carries a suffix marking it as the paid flavour of the same application, so the free listing and the store version are not obviously the same artefact.

No internet access, and a sync feature

The first block of features makes the privacy argument explicitly: no ads, no annoying popups, and no internet access needed, which the readme ties to privacy, security, and stability rather than leaving the claim floating. The problem is that the next blocks contradict it. There is CalDAV support for syncing with hosted calendar services, an interoperability line naming several of them by vendor, a share action for getting an event out through social media and email, and a store listing for the application. None of those are problems in themselves; a calendar that syncs can still work offline between syncs. But the marketing sentence and the feature list describe two different products, and a reader who installs on the strength of the first one is going to meet the second one.

Events come in from outside and go back out

The data model is more generous than the offline framing suggests. The widget supports exporting and importing events through the standard calendar file format, and the whole settings file can be exported as text and imported on another device, which is the pattern people use when moving to a new phone. Event creation is described as flexible in times, duration, reminders, and repetition rules. There is duplicate detection for families, with an organisational feature for copying an event and managing several people at once, plus an importer for public holidays, contact birthdays, and anniversaries. That last one is the most useful item on the list and the least mentioned, since a calendar that knows your contacts' birthdays is worth more than most of the sharing features.

Five views, a list mode, and a filter by type

The readme describes switching between daily, weekly, monthly, yearly, and event-focused views, and then adds the option most people actually use: a plain list of upcoming events instead of a month grid. For a personal planner that list is the feature, and it is buried in a paragraph about the monthly view. Two smaller capabilities sit alongside it. Personal events can be filtered quickly by type, which is how you separate work from family without colour-coding everything. And an event's location is shown on a map, which is quietly useful for anything with an address attached.

Customisation is concentrated in the widget and the alarm

Almost every customisation option is about the home-screen widget or about notifications. The widget is offered with a large number of options for reminders, notification appearance, the small month view inside it, and overall appearance. On the alarm side, the sound, whether it loops, which audio stream it uses, and the vibration pattern are all configurable, and the themes and per-calendar colours are there too. What is absent is equally notable: the readme promises no complicated features, and there is no sign of anything approaching a plug-in system, external integrations beyond the calendar sync, or an account of your own. There is also a promise about permissions, stated in the same breath as the ads: no unnecessary ones, which for a calendar app means no request for contacts, location, or storage beyond what the calendar and its widget need. It is a local-first app with a customisable surface, which is a defensible thing to be, and the permission claim is the part of that positioning a technical reader can verify by installing it and watching what it asks for.

A keystore template sits next to the build file

The repository root shows how a released Android application is put together. There is a sample keystore properties file, which is the standard way to keep signing credentials out of version control while telling the build where they live, so a fork needs its own keys before it can produce an installable build of the same shape. A release automation directory sits alongside it, which is how the store listings get their text and screenshots, and a graphics directory holds the artwork that automation consumes. The rest is conventional: an application module, the Kotlin build scripts, a properties file, the wrapper for both shell families, and the usual editor and ignore files. Nothing here is unusual, and the keystore sample is the one file worth reading before you start a fork.

Thirty languages, and a donation list instead of a price

The last section is a support page rather than a paywall. It lists a bank transfer reference and then five cryptocurrency networks with their addresses, followed by two payment platforms and a membership page. Nowhere in the file is a price stated, and the application is described as open source, which is the arrangement most of these projects converge on: the build is free and the funding is voluntary. The translation count is the other number worth noting, since more than thirty languages is a real maintenance commitment for a project whose releases stopped in 2023, and it is one more reason to check the current state of the store listing before you plan around a specific version.

Editorial conclusion

This app fits someone who wants a calendar that opens instantly on a train, shows no ads, and does not demand permissions it does not need. Two things to check before you install. Read the privacy claim against the feature list, because the app markets itself as working with no internet access while offering exchange sync and sharing, so what leaves the device is worth understanding on your own setup. And note the maintenance dates, since the last tagged release and the last commit are both older than the year the app names itself after.

Frequently asked questions

Official sources

1. Official documentation
2. Official README
3. Project repository
4. Release notes