-    $query = qq|UPDATE ap SET paid = ? WHERE id = ?|;
-    do_query($form, $dbh, $query, $form->{invpaid}, conv_i($form->{id}));
+    $query = qq|UPDATE ap SET paid = ?, datepaid = ? WHERE id = ?|;
+    do_query($form, $dbh, $query,  $form->{invpaid}, $form->{invpaid} ? conv_date($form->{datepaid}) : undef, conv_i($form->{id}));
+  }
+
+  IO->set_datepaid(table => 'ap', id => $form->{id}, dbh => $dbh);
+
+  # safety check datev export
+  if ($::instance_conf->get_datev_check_on_ap_transaction) {
+    my $transdate = $::form->{transdate} ? DateTime->from_lxoffice($::form->{transdate}) : undef;
+    $transdate  ||= DateTime->today;
+
+    my $datev = SL::DATEV->new(
+      exporttype => DATEV_ET_BUCHUNGEN,
+      format     => DATEV_FORMAT_KNE,
+      dbh        => $dbh,
+      from       => $transdate,
+      to         => $transdate,
+    );
+
+    $datev->export;
+
+    if ($datev->errors) {
+      $dbh->rollback;
+      die join "\n", $::locale->text('DATEV check returned errors:'), $datev->errors;
+    }