Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

android communication email mozilla
40 Open Issues Need Help Last updated: Mar 4, 2026

Open Issues Need Help

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type: bug good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla

AI Summary: This issue requests a warning message to be displayed when a user attempts to edit or send a message while offline. Currently, messages are silently moved to an outbox, leading users to mistakenly believe their message has been sent. The proposed feature aims to prevent confusion by explicitly informing users about their connection status before they attempt to send or edit a message.

Complexity: 2/5
type: bug good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: bug good first issue type: regression

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: bug good first issue type: accessibility

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: enhancement good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla

AI Summary: The user is encountering a persistent "Sent folder not found" error in Thunderbird for Android v15.0 every time they send or reply to an email. This issue occurs despite the user explicitly setting their "Sent folder" to "None" and disabling "Upload sent messages to Sent folder," indicating the app is attempting to access a non-existent folder against user preferences.

Complexity: 3/5
type: bug good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: enhancement good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: bug good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: enhancement good first issue rls

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: bug good first issue status: answered

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: bug good first issue status: answered

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: bug good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: bug good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: bug good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: enhancement good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla

AI Summary: Users are experiencing a bug in K-9 Mail where email addresses in the Cc: and Bcc: fields are duplicated or multiplied after changing the screen orientation from portrait to landscape and back to portrait. This occurs when automated screen orientation is enabled, and Cc/Bcc fields are always visible, potentially with a default Bcc address configured.

Complexity: 3/5
type: bug good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: bug good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: bug good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: bug good first issue type: UI/UX

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: enhancement good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: bug good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: enhancement good first issue rls

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: enhancement good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: bug good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: bug good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: bug good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: bug good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla
type: bug good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla

AI Summary: Add an accessible label, such as "Navigate up", to the back button on the Thunderbird for Android account general settings page to improve accessibility for users.

Complexity: 2/5
type: bug good first issue type: accessibility

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla

AI Summary: The task is to fix a bug in the Thunderbird for Android email app where the "Show headers" feature collapses multi-line headers into a single line, making them unreadable. The fix requires investigating the header display logic within the app's codebase and modifying it to preserve newline characters and potentially use a fixed-width font for better readability. This likely involves examining the code responsible for parsing and rendering email headers.

Complexity: 4/5
type: enhancement good first issue priority: low

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla

AI Summary: Fix a UI rendering issue in Thunderbird for Android (version 11.0.b3) where the "Download Complete Message" button is obscured by the bottom navigation bar on Samsung A52s 5G running Android 14. The task involves investigating the layout and potentially adjusting the positioning or sizing of UI elements to ensure the button is always visible and clickable.

Complexity: 4/5
type: bug good first issue

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

Kotlin
#android#communication#email#mozilla