diff --git a/lib/Travelynx/Command/database.pm b/lib/Travelynx/Command/database.pm
index 4f7c792..eb2443c 100644
--- a/lib/Travelynx/Command/database.pm
+++ b/lib/Travelynx/Command/database.pm
@@ -1,4 +1,5 @@
 package Travelynx::Command::database;
+
 # Copyright (C) 2020 Daniel Friesel
 #
 # SPDX-License-Identifier: AGPL-3.0-or-later
@@ -1055,6 +1056,19 @@ my @migrations = (
 			}
 		);
 	},
+
+	# v23 -> v24
+	# travelynx 1.22 warns about upcoming account deletion due to inactivity
+	sub {
+		my ($db) = @_;
+		$db->query(
+			qq{
+				alter table users add column deletion_notified timestamptz;
+				comment on column users.deletion_notified is 'Time at which warning about upcoming account deletion due to inactivity was sent';
+				update schema_version set version = 24;
+			}
+		);
+	},
 );
 
 sub setup_db {
diff --git a/lib/Travelynx/Command/maintenance.pm b/lib/Travelynx/Command/maintenance.pm
index 5f609cb..58189ff 100644
--- a/lib/Travelynx/Command/maintenance.pm
+++ b/lib/Travelynx/Command/maintenance.pm
@@ -18,6 +18,7 @@ sub run {
 	my $verification_deadline = $now->clone->subtract( hours => 48 );
 	my $deletion_deadline     = $now->clone->subtract( hours => 72 );
 	my $old_deadline          = $now->clone->subtract( years => 1 );
+	my $old_notification_deadline = $now->clone->subtract( weeks => 4 );
 
 	my $db = $self->app->pg->db;
 	my $tx = $db->begin;
@@ -82,12 +83,39 @@ sub run {
 		printf( "Pruned %d pending mail change(s)\n", $rows );
 	}
 
+	my $to_notify = $db->select(
+		'users',
+		[ 'id', 'name', 'email', 'last_seen' ],
+		{
+			last_seen         => { '<', $old_deadline },
+			deletion_notified => undef
+		}
+	);
+
+	for my $user ( $to_notify->hashes->each ) {
+		$self->app->sendmail->age_deletion_notification(
+			name        => $user->{name},
+			email       => $user->{email},
+			last_seen   => $user->{last_seen},
+			login_url   => $self->app->base_url_for('login')->to_abs,
+			account_url => $self->app->base_url_for('account')->to_abs,
+			imprint_url => $self->app->base_url_for('impressum')->to_abs,
+		);
+		$self->app->users->mark_deletion_notified( uid => $user->{id} );
+	}
+
 	my $to_delete = $db->select( 'users', ['id'],
 		{ deletion_requested => { '<', $deletion_deadline } } );
 	my @uids_to_delete = $to_delete->arrays->map( sub { shift->[0] } )->each;
 
-	$to_delete
-	  = $db->select( 'users', ['id'], { last_seen => { '<', $old_deadline } } );
+	$to_delete = $db->select(
+		'users',
+		['id'],
+		{
+			last_seen         => { '<', $old_deadline },
+			deletion_notified => { '<', $old_notification_deadline }
+		}
+	);
 
 	push( @uids_to_delete,
 		$to_delete->arrays->map( sub { shift->[0] } )->each );
diff --git a/lib/Travelynx/Helper/Sendmail.pm b/lib/Travelynx/Helper/Sendmail.pm
index 8a7b1f1..376861d 100644
--- a/lib/Travelynx/Helper/Sendmail.pm
+++ b/lib/Travelynx/Helper/Sendmail.pm
@@ -1,4 +1,5 @@
 package Travelynx::Helper::Sendmail;
+
 # Copyright (C) 2020 Daniel Friesel
 #
 # SPDX-License-Identifier: AGPL-3.0-or-later
@@ -41,4 +42,34 @@ sub custom {
 	return try_to_sendmail($reg_mail);
 }
 
+sub age_deletion_notification {
+	my ( $self, %opt ) = @_;
+	my $name        = $opt{name};
+	my $email       = $opt{email};
+	my $last_seen   = $opt{last_seen};
+	my $login_url   = $opt{login_url};
+	my $account_url = $opt{account_url};
+	my $imprint_url = $opt{imprint_url};
+
+	my $body = "Hallo ${name},\n\n";
+	$body
+	  .= "Dein travelynx-Account wurde seit dem ${last_seen} nicht verwendet.\n";
+	$body
+	  .= "Im Sinne der Datensparsamkeit wird er daher in vier Wochen gelöscht.\n";
+	$body
+	  .= "Falls du den Account weiterverwenden möchtest, kannst du dich unter\n";
+	$body .= "<$login_url> anmelden.\n";
+	$body
+	  .= "Durch die Anmeldung wird die Löschung automatisch abgebrochen.\n\n";
+	$body
+	  .= "Falls du den Account löschen, aber zuvor deine Daten exportieren möchtest,\n";
+	$body .= "kannst du dich unter obiger URL anmelden, unter <$account_url>\n";
+	$body
+	  .= "deine Daten exportieren und anschließend den Account löschen lassen.\n\n\n";
+	$body .= "Impressum: ${imprint_url}\n";
+
+	return $self->custom( $email,
+		'travelynx: Löschung deines Accounts', $body );
+}
+
 1;
diff --git a/lib/Travelynx/Model/Users.pm b/lib/Travelynx/Model/Users.pm
index 1371b8a..70d81c4 100644
--- a/lib/Travelynx/Model/Users.pm
+++ b/lib/Travelynx/Model/Users.pm
@@ -23,8 +23,25 @@ sub mark_seen {
 
 	$db->update(
 		'users',
-		{ last_seen => DateTime->now( time_zone => 'Europe/Berlin' ) },
-		{ id        => $uid }
+		{
+			last_seen         => DateTime->now( time_zone => 'Europe/Berlin' ),
+			deletion_notified => undef
+		},
+		{ id => $uid }
+	);
+}
+
+sub mark_deletion_notified {
+	my ( $self, %opt ) = @_;
+	my $uid = $opt{uid};
+	my $db  = $opt{db} // $self->{pg}->db;
+
+	$db->update(
+		'users',
+		{
+			deletion_notified => DateTime->now( time_zone => 'Europe/Berlin' ),
+		},
+		{ id => $uid }
 	);
 }