About K-9 Mail
K-9 Mail is an email client built for Android and developed by Mozilla Thunderbird, filed under the communication category. It gives you a dedicated place to handle your mail on a phone or tablet, and this listing covers version 24.0, a release dated 2026-10-07.
What the app is for As a communication tool, K-9 Mail centers entirely on reading and sending electronic mail from a mobile device. It is offered by Mozilla Thunderbird, an organization long associated with desktop mail software, so the app follows that lineage with a focused, single-purpose design rather than a bundle of unrelated features.
Compatibility and setup The build requires Android 6.0 or newer. If your handset runs a more recent release of the platform, it should fall within the supported range, while devices below that baseline will not be able to install it. Once installed, the app is identified by the package name com.fsck.k9, which is useful if you need to locate it in your device settings or check which build is present.
Size and footprint The installation file measures 10.9 MB, keeping it modest compared with many modern applications. That small footprint leaves plenty of room for your messages, attachments, and account data without putting heavy demands on available storage. The content rating for this listing is unknown, so the listing gives no age guidance for families.
Version details Version 24.0 is the build described here. Noting the version number is a simple way to confirm you are running the release documented in this listing, and the package name com.fsck.k9 ties the installed app back to this exact package record.
APK Information
- Version
- 24.0
- Size
- 10.9 MB
- Android
- 6.0+
- File type
- APK
- Updated
- Oct 7, 2026
- Package
- com.fsck.k9
- Developer
- Mozilla Thunderbird
Features
Email client
Communication
Thunderbird developer
Android mail
Frequently Asked Questions
Which Android versions can run this app?
The build requires Android 6.0 or newer. If your device runs that release or anything more recent, it falls within the stated compatibility range. Devices running an older release will not be able to install the package. The listing does not describe any additional hardware or screen requirements beyond the Android baseline.
How much storage should I free up before installing?
The installation file measures 10.9 MB, so that is the space needed for the package itself. Your device will also need room for account settings, message bodies, and attachments once the app is running, but those amounts depend on your own mail usage rather than anything stated in this listing.
What package name does this app install under?
The package name is com.fsck.k9. You can use it to confirm which app you have installed, to find it in your device's application list, or to distinguish it from any other mail client sharing a similar display name. The same package identifier is tied to version 24.0 in this listing.
Which version is documented on this listing?
The version documented here is 24.0, released 2026-10-07. Comparing this number against what is shown on your device tells you whether you are running the described build. The listing covers only this single version and does not describe earlier releases or their changes.
Who develops the app and what category is it in?
K-9 Mail is developed by Mozilla Thunderbird and is filed under the communication category. It is a straightforward mail-focused application from a developer with a background in mail software, which is reflected in the app's narrow purpose: handling email correspondence on an Android device.
