Mailflag email notification filter

Mailflag is a notification service for IMAP IDLE, offering five different modes of operation.
- Foreground Service runs with a small icon in the notification area (more persistent).
- Partial Wake Lock (foreground service) keeps the device awake (most persistent, increased power usage).
- Background Service (Android 7- only) runs without permanent icon (less persistent).
- Polling checks periodically for 'unseen' mails (lowest power usage).
- External Intent performs a single poll by intent "com.bryk.mailflag.POLL" to "com.bryk.mailflag(.StartReceiver)".

The first three (idling) modes provide instant response; a single poll is performed after connection loss.
Polling flags all messages to avoid repeated notification.

You may need to check the WiFi Sleep Policy of your device.
With Android 6.0+ Mailflag will ask (once) for exclusion from Battery Optimization ('Doze mode').

Configurable filters limit notifications to specific (groups of) senders, subjects, To/CC addresses and body content.
Each filter may contain multiple ||-separated strings. A string within slashes is evaluated as regular expression.
Examples (explained) can be found on the Mailflag web page.
Notification sound, LED color, etc. are configurable using the Options menu.
The new mail notification can launch any non-system app with a (package) name containing 'mail'.
The notification shows 'Mailflag:' in its title, which allows detection by e.g. Tasker (%NTITLE variable).

Mailflag can add a custom prefix to the subject of rejected (not notified) mail. Email clients that provide basic filtering (such as 'Email Spam Blocker' from Maxlab) can use this prefix to move the mail to a different folder.
Note: adding a prefix is not possible on gmail servers.

The current version supports a single connection using imaps (strict/any) for SSL, imap for NON-SSL.
Backup/Restore allows easy switching between different accounts.

Mailflag will run with a trial limitation until a license is purchased (in-app purchase,). The application is fully functional, but the service stops after 72 hours. The license removes this 72 hour limitation.
PLEASE RUN MAILFLAG IN TRIAL MODE FIRST, TO VERIFY THAT IT RUNS ON YOUR DEVICE AND MEETS YOUR EXPECTATIONS.

IMPORTANT PERMISSIONS
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WRITE_EXTERNAL_STORAGE: enable Mailflag to backup/restore all settings and options.
REQUEST_IGNORE_BATTERY_OPTIMIZATION: keep Mailflag functioning when the screen is off.

Under Android 6.0+ Mailflag will ask to grant these permissions.

Privacy statement
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Mailflag does not collect data and no data leaves your device in any way.

Recent changes:
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