Premium
Download K-9 Mail 18.0 APK
Supports installation on external storage.
Target: Android 15 (API 35)
nodpi
What's new in K-9 Mail 18.0
K-9 Mail version 18.0
New:
- PNG avatars
- Setting to display ISO date/time in message list
- Fixed-width font for composing
Changed:
- Attachment summary moved to header
Fixed:
- "Delete (from notification)" setting did not retain state
- Find folder search hint text was cut off
- User not notified if offline when sending message
- CC/BCC fields were not expanded by default for Reply All
- Crash occurred when retrieving images
- Deleted messages could remain visible in message list
About K-9 Mail 18.0
K-9 Mail is an open source email client that works with basically every email provider.
Premium
Features
* supports multiple accounts
* Unified Inbox
* privacy-friendly (no tracking whatsoever, only connects to your email provider)
* automatic background synchronization or push notifications
* local and server-side search
* OpenPGP email encryption (PGP/MIME)
Install the app "OpenKeychain: Easy PGP" to encrypt/decrypt your emails using OpenPGP.
Support
If you're having trouble with K-9 Mail, ask for help in our support forum at forum.k9mail.app
Want to help?
K-9 Mail is now part of the Thunderbird family and remains a community developed project. If you're interested in helping to improve the app, please join us! You can find our bug tracker, source code, and wiki at github.com/thunderbird/thunderbird-android
We're always happy to welcome new developers, designers, documenters, translators, bug triagers and friends.
K-9 Mail 18.0 variants
This release may come in several variants. Consult our handy FAQ to see which download is right for you.
Version:18.0
Uploaded:April 17, 2026 at 5:46PM UTC
File size:9.48 MB
Downloads:6
Version:21.0
Uploaded:July 23, 2026 at 6:28PM UTC
File size:10.19 MB
Version:21.0(39041) for Android 6.0+ (Marshmallow, API 23)
Uploaded:July 21, 2026 at 2:21PM UTC
File size:10.67 MB
Downloads:34
Version:20.1(39040) for Android 6.0+ (Marshmallow, API 23)
Uploaded:July 9, 2026 at 2:02PM UTC
File size:10.57 MB
Downloads:46
Version:20.0(39039) for Android 6.0+ (Marshmallow, API 23)
Uploaded:June 23, 2026 at 2:13AM UTC
File size:10.11 MB
Downloads:53
Version:19.2(39038) for Android 6.0+ (Marshmallow, API 23)
Uploaded:June 5, 2026 at 1:37AM UTC
File size:10.56 MB
Downloads:57
Version:19.0(39036) for Android 6.0+ (Marshmallow, API 23)
Uploaded:May 29, 2026 at 12:34AM UTC
File size:10.05 MB
Downloads:36
Version:18.0(39035) for Android 6.0+ (Marshmallow, API 23)
Uploaded:April 19, 2026 at 4:14PM UTC
File size:9.94 MB
Downloads:119
Version:17.0(39034) for Android 6.0+ (Marshmallow, API 23)
Uploaded:March 24, 2026 at 1:32PM UTC
File size:14.01 MB
Downloads:77
Version:21.0
Uploaded:July 21, 2026 at 2:21PM UTC
File size:10.67 MB
Downloads:34
Version:20.1
Uploaded:July 9, 2026 at 2:02PM UTC
File size:10.57 MB
Downloads:46
Version:20.0
Uploaded:June 23, 2026 at 2:13AM UTC
File size:10.11 MB
Downloads:53
Version:19.2
Uploaded:June 5, 2026 at 1:37AM UTC
File size:10.56 MB
Downloads:57
Version:19.0
Uploaded:May 29, 2026 at 12:34AM UTC
File size:10.05 MB
Downloads:36
Version:18.0
Uploaded:April 19, 2026 at 4:14PM UTC
File size:9.94 MB
Downloads:119
Version:17.0
Uploaded:March 24, 2026 at 1:32PM UTC
File size:14.01 MB
Downloads:77
Version:16.1
Uploaded:February 28, 2026 at 6:54PM UTC
File size:13.36 MB
Downloads:146
Version:16.0
Uploaded:February 3, 2026 at 6:14PM UTC
File size:13.36 MB
Downloads:89
Version:15.0
Uploaded:January 12, 2026 at 3:40PM UTC
File size:13.29 MB
Downloads:62
