Fossify Calendar

Fossify Calendar is an open-source calendar from Fossify, the community project that took over the Simple Mobile Tools apps after they were discontinued in late 2023. It carries on from Simple Calendar Pro, and Fossify fixed its import to stay compatible with Simple Calendar’s data.

What it does

From the project’s README and the app itself:

• Views by day, week, month and year, plus an event list.
• Recurring events and reminders, with a choice of sound, snooze, and reminders that repeat until you dismiss them.
• Public holidays for 70 countries, Brazil’s regional holidays included, built into the app. Since version 1.11.0 they update automatically; if you imported holidays before, pick your countries again; the app warns that holidays imported the old way may have to be deleted by hand.
• Birthdays and anniversaries from your contacts, added automatically if you like.
• Tasks alongside events, and a time zone per event if you need one.
• Import and export .ics files, open .ics files from other apps, and back up your events automatically.
• Three widgets: a month view, an event list and today’s date.

Sync needs another app

Fossify Calendar doesn’t sync by itself, and Fossify runs no sync service. It shows calendars that another app keeps in sync: Google’s own Calendar app for a Google account, or a sync adapter such as DAVx⁵ for CalDAV servers like Nextcloud. Version 1.11.0 fixed CalDAV sync on Android 11 and later.

Good to know

• The APK doesn’t request internet access; the calendar itself works entirely on the phone.
• The developers have confirmed a bug they are treating as urgent: a finished task can turn back to unfinished after you edit it.

About this file

• This is Fossify’s own build of version 1.11.0, from September 2026, delivered through IzzyOnDroid and signed by Fossify. It is byte for byte the APK on the project’s GitHub release and the one F-Droid distributes.
• Fossify says its Google Play and F-Droid releases use the same package name and signing key, so this file can be installed over the Play version when it is the same version or newer. In the source code, the Play build now and then asks you to buy Fossify’s Thank You app; this build doesn’t.
• The 7.8 MB file runs on Android 8.0 and later and declares 12 permissions.

CPU types in this build: arm64-v8a (64-bit ARM, almost every phone since 2017); armeabi-v7a (32-bit ARM, older and budget phones); x86 (32-bit Intel, emulators); x86_64 (64-bit Intel, emulators and Chromebooks).

Versions currently kept in the IzzyOnDroid repository. We host and check only the newest one. Full changelog.