Great when it works, but for the past few weeks it has stopped syncing, it says syncing disabled at the top but all the settings are correct. I have tried uninstalling and reinstalling to no avail. Missing important e-mails when they come in due to this, and having to constantly manually refresh the email in order the check for messages. Also opening messages has slowed significantly, even just plain text messages take 20-30 seconds to load. Would be five stars if not for these issues.
Works great with Android 7.0 after a few setting changes. Go to your phone settings, battery and optimized battery usage. Scroll down to K-9 Mail and make sure it is turned off, next go to default application settings and set K-9 Mail as your default mail application, if you have trouble changing to default, install 'Default Application Manager Lite' from the play store. Now K-9 Mail will automatically sync when screen is off... Enjoy!
Encryption features get better. One important one missing though: Should allow to save messages unencrypted if the server is trusted. This option is crucial for more user friendly work. Also: opening messages got quite slow since some updates ago. If both issues were solved it would be 5 star!
Update (June 2017) stopped synchronizing. Lowered my rating, but not yet uninstalling. /// Update (Dec 2015). Still by far the best email client. /// (2013) I have used K9 for several years for my non-gmail account. The current official version is 4.409, and it is excellent. However, today I installed the latest version posted at the K9 Mail developer's site, 4.512, and additional improvements make this email client stand out by some distance. Even in comparison with Gmail. Wow!
Used to be the best mail app I used but the latest update has changed how notifications work. Instead of going straight to an account's inbox it just goes to a list of folders instead which means an extra tap... An option would have been great for any UI changes. Reading mail was a lot quicker before this. It's also getting quite buggy... Emptying trash doesn't free up space any more. Either numbers not updating or it's really not being freed. Sometimes an old email gets marked as unread or suddenly my emails are duplicated... Some aesthetic update wouldn't hurt like some icons.
I've used this app for several years and the fact I could easily set it up for multiple self hosted accounts was initially what drew me to it. Lately I've noticed all too often connections are not released on the server end and due to that ill have to ditch K9 for something else. If that issue could be resolved I may come back
Changes in 5.206:
• Fixed crash when starting the app from the unread widget
Changes in 5.205:
• Fixed bug where the message body wasn't displayed when no crypto provider was configured
Changes in 5.204:
• Fixed bug where not all data was removed for deleted messages
• Improved support for messages that didn't display correctly
• Fixed bug with notification actions sometimes not working
• Use "encrypted.asc" as filename for PGP/MIME emails
• Updated translations
• Many more bug fixes
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